Guarantor Financial Statements (Condensed Consolidating Statement of Operations and Comprehensive Income) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 30, 2013	Mar. 31, 2012
Condensed Financial Statements, Captions [Line Items]
Net Sales	$ 519.1	$ 522.8
Cost of products sold (COGS)	377.6	376.8
Gross profit	141.5	146.0
Selling, general and administrative expense, net (SG&A)	125.6	110.1
Amortization of intangible assets	11.3	11.0
Operating earnings	4.6	24.9
Interest expense	(24.6)	(24.5)
(Loss) earnings before (benefit) provision for income taxes	(20.0)	0.4
Charges and allocations to subsidiaries and equity in subsidiaries' earnings (loss) before income taxes	0	0
Earnings (loss) before provision (benefit) for income taxes	(20.0)	0.4
(Benefit) provision for income taxes	(4.9)	1.6
Net loss	(15.1)	(1.2)
Comprehensive (loss) income	(18.1)	0.7
Nortek [Member]
Condensed Financial Statements, Captions [Line Items]
Net Sales	0	0
Cost of products sold (COGS)	0	0
Gross profit	0	0
Selling, general and administrative expense, net (SG&A)	16.9	7.8
Amortization of intangible assets	0	0
Operating earnings	(16.9)	(7.8)
Interest expense	(23.8)	(23.6)
(Loss) earnings before (benefit) provision for income taxes	(40.7)	(31.4)
Charges and allocations to subsidiaries and equity in subsidiaries' earnings (loss) before income taxes	20.7	31.8
Earnings (loss) before provision (benefit) for income taxes	(20.0)	0.4
(Benefit) provision for income taxes	(4.9)	1.6
Net loss	(15.1)	(1.2)
Comprehensive (loss) income	(18.1)	0.7
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net Sales	433.9	421.6
Cost of products sold (COGS)	317.9	301.3
Gross profit	116.0	120.3
Selling, general and administrative expense, net (SG&A)	85.7	82.3
Amortization of intangible assets	10.8	10.3
Operating earnings	19.5	27.7
Interest expense	(0.7)	(0.7)
(Loss) earnings before (benefit) provision for income taxes	18.8	27.0
Charges and allocations to subsidiaries and equity in subsidiaries' earnings (loss) before income taxes	(16.2)	(14.3)
Earnings (loss) before provision (benefit) for income taxes	2.6	12.7
(Benefit) provision for income taxes	0.1	4.8
Net loss	2.5	7.9
Comprehensive (loss) income	2.6	7.9
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net Sales	172.0	165.7
Cost of products sold (COGS)	146.4	139.9
Gross profit	25.6	25.8
Selling, general and administrative expense, net (SG&A)	23.0	20.0
Amortization of intangible assets	0.7	0.7
Operating earnings	1.9	5.1
Interest expense	(0.1)	(0.2)
(Loss) earnings before (benefit) provision for income taxes	1.8	4.9
Charges and allocations to subsidiaries and equity in subsidiaries' earnings (loss) before income taxes	0.2	0.1
Earnings (loss) before provision (benefit) for income taxes	2.0	5.0
(Benefit) provision for income taxes	0.9	3.0
Net loss	1.1	2.0
Comprehensive (loss) income	(2.1)	4.2
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net Sales	(86.8)	(64.5)
Cost of products sold (COGS)	(86.7)	(64.4)
Gross profit	(0.1)	(0.1)
Selling, general and administrative expense, net (SG&A)	0	0
Amortization of intangible assets	(0.2)	0
Operating earnings	0.1	(0.1)
Interest expense	0	0
(Loss) earnings before (benefit) provision for income taxes	0.1	(0.1)
Charges and allocations to subsidiaries and equity in subsidiaries' earnings (loss) before income taxes	(4.7)	(17.6)
Earnings (loss) before provision (benefit) for income taxes	(4.6)	(17.7)
(Benefit) provision for income taxes	(1.0)	(7.8)
Net loss	(3.6)	(9.9)
Comprehensive (loss) income	$ (0.5)	$ (12.1)