Acquisitions (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended	3 Months Ended	9 Months Ended
	Jan. 31, 2012	Sep. 30, 2012	Sep. 30, 2012
Acquisitions
Cash payment			$ 14.1
Purchase price allocation
Acquisition integration costs		0.3	4.7
Wausau Paper Mills, LLC
Acquisitions
Cash payment	21.0
Period of finished goods inventory (in months)	1 month
Purchase price allocation
Acquisition integration costs		0.3	4.7
Wausau Paper Mills, LLC | Minimum
Purchase price allocation
Expected acquisition integration costs			5.0
Wausau Paper Mills, LLC | Maximum
Purchase price allocation
Expected acquisition integration costs			6.0
Wausau Paper Mills, LLC | Level 2
Purchase price allocation
Finished goods inventory	6.6
Total assets at fair value	6.6
Wausau Paper Mills, LLC | Level 3
Purchase price allocation
Property, plant and equipment	0.9
Total assets at fair value	14.6
Wausau Paper Mills, LLC | Total
Purchase price allocation
Finished goods inventory	6.6
Property, plant and equipment	0.9
Total assets at fair value	21.2
Wausau Paper Mills, LLC | Trade names | Level 3
Purchase price allocation
Intangible assets	11.5
Wausau Paper Mills, LLC | Trade names | Total
Purchase price allocation
Intangible assets	11.5
Wausau Paper Mills, LLC | Customer based intangibles | Level 3
Purchase price allocation
Intangible assets	2.0
Wausau Paper Mills, LLC | Customer based intangibles | Total
Purchase price allocation
Intangible assets	2.0
Wausau Paper Mills, LLC | Trade names and trademarks | Level 3
Purchase price allocation
Intangible assets	0.2
Wausau Paper Mills, LLC | Trade names and trademarks | Total
Purchase price allocation
Intangible assets	$ 0.2