Business Segment and Geographic Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012 item	Dec. 31, 2011	Dec. 31, 2010
Business Segment and Geographic Information
Number of reportable segments									2
Business segment information
Net sales	$ 192.6	$ 206.3	$ 211.7	$ 198.2	$ 165.5	$ 174.9	$ 182.9	$ 172.7	$ 808.8	$ 696.0	$ 657.7
Operating income (loss)	15.9	16.3	22.0	16.2	13.6	12.5	15.7	14.8	70.4	56.6	55.1
Integration costs related to acquisition of Wausau Brands									5.8
Gain related to the sale of the Ripon Mill											3.4
SERP settlement charge				3.5					3.5
Loss on retirement of bonds								2.4	0.6	2.4
Depreciation and amortization									28.8	31.0	31.3
Capital expenditures									25.1	23.1	17.4
TOTAL ASSETS	610.7				565.1				610.7	565.1
United States
Business segment information
Net sales									543.4	416.2	413.6
TOTAL ASSETS	322.5				286.4				322.5	286.4
Canada
Business segment information
TOTAL ASSETS	0.2				0.3				0.2	0.3
Europe
Business segment information
Net sales									265.4	279.8	244.1
TOTAL ASSETS	288.0				278.4				288.0	278.4
Technical Products
Business segment information
Net sales									406.6	421.1	384.3
Operating income (loss)									37.6	33.8	29.2
Depreciation and amortization									15.7	17.6	16.9
Capital expenditures									14.7	18.0	10.7
TOTAL ASSETS	348.5				336.3				348.5	336.3
Fine Paper
Business segment information
Net sales									372.7	274.9	273.4
Operating income (loss)									50.0	39.7	40.5
Integration costs related to acquisition of Wausau Brands									5.8
Gain related to the sale of the Ripon Mill											3.4
Depreciation and amortization									9.4	9.5	9.7
Capital expenditures									10.2	4.2	6.7
TOTAL ASSETS	214.0				162.2				214.0	162.2
Other
Business segment information
Net sales									29.5
Operating income (loss)									2.4
Unallocated corporate costs
Business segment information
Operating income (loss)									(19.6)	(16.9)	(14.6)
SERP settlement charge									3.5
Loss on retirement of bonds									0.6	2.4
Corporate and Other
Business segment information
Depreciation and amortization									3.7	3.9	4.7
Capital expenditures									0.2	0.9
TOTAL ASSETS	$ 48.2				$ 66.6				$ 48.2	$ 66.6