Property, Plant and Equipment (Details 1) (USD $) In Thousands, unless otherwise specified	0 Months Ended	12 Months Ended					12 Months Ended	3 Months Ended	12 Months Ended
	Mar. 29, 2013	Nov. 30, 2013	Dec. 01, 2012	Dec. 03, 2011	Dec. 01, 2012 Land [Member]	Dec. 01, 2012 Building and Building Improvements [Member]	Nov. 30, 2013 Cost of Sales [Member]	Aug. 31, 2013 Air Filtration [Member] Cost of Sales [Member]	Nov. 30, 2013 Accounts Payable and Accrued Liabilities [Member]	Dec. 01, 2012 Accounts Payable and Accrued Liabilities [Member]
Property, Plant and Equipment [Line Items]
Land		$ 9,444	$ 9,326
Buildings and building fixtures		119,207	107,857
Machinery and equipment		388,669	372,358
Construction in process		24,420	20,578
Property, plant and equipment, at cost, gross		541,740	510,119
Accumulated depreciation		(332,787)	(315,018)
Property, plant and equipment, at cost, less accumulated depreciation		208,953	195,101	184,992
Assets held for sale		0	2,000		398	1,602
Proceeds from disposition of plant assets	2,211	3,373	534	327
Gain on the sale of assets		(3,862)	725	(452)			211	4,631
Expenses capitalized									1,700	1,668
Capital Lease Obligations Incurred		$ 270	$ 826