Significant Accounting Policies - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	1 Months Ended		12 Months Ended
	Jul. 31, 2012	Sep. 30, 2011	Dec. 31, 2012 Facility	Dec. 31, 2011	Dec. 31, 2010
Significant Accounting Policies [Line Items]
Number of production plants			6
Allowance for doubtful accounts			$ 1,844	$ 1,933
Other receivables			1,732	1,968
Disposal or impairment of various assets, loss			(518)	(1,548)	(1,449)
Interest percentage in cost method investee				6.00%
Impairment of goodwill				889	470
Research and development expenses			$ 6,916	$ 7,335	$ 5,279
Intangible impairment likelihood percentage	50.00%
Goodwill impairment more likelihood than not percentage		50.00%
Georgia and Alabama
Significant Accounting Policies [Line Items]
Area of land and leasehold interests			4,150
Marshfield, Wisconsin
Significant Accounting Policies [Line Items]
Area of land and leasehold interests			490
Maximum
Significant Accounting Policies [Line Items]
Receivables collection period			30 days
Maturity period for all highly liquid investments when purchased to be cash equivalents			3 months
Capitalized software estimated useful life			5 years