Guarantor Financial Statements (Condensed Consolidating Statement of Operations and Comprehensive Income) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 29, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Oct. 01, 2011	Jul. 02, 2011	Apr. 02, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Condensed Financial Statements, Captions [Line Items]
Net Sales	$ 505.4	$ 557.4	$ 615.7	$ 522.8	$ 535.2	$ 551.8	$ 564.9	$ 488.6	$ 2,201.3	$ 2,140.5	$ 1,899.3
Cost of products sold									1,560.9	1,567.8	1,391.8
Gross profit	152.2	158.4	183.8	146.0	150.7	142.2	152.8	127.0	640.4	572.7	507.5
Selling, general and administrative expense, net	125.7	113.6	119.1	110.1	113.4	117.1	121.1	113.2	468.5	464.8	399.9
Amortization of intangible assets									44.3	44.8	37.0
Operating earnings	15.2	33.8	53.7	24.9	26.4	14.0	20.8	1.9	127.6	63.1	70.6
Interest expense									(96.5)	(105.6)	(95.7)
Loss from debt retirement									(6.4)	(33.8)	0
Investment income									0.1	0.1	0.1
(Loss) income before charges and allocations to subsidiaries and equity in subsidiaries' earnings (loss) before income taxes									24.8	(76.2)	(25.0)
Charges and allocations to subsidiaries and equity in subsidiaries' earnings (loss) before income taxes									0	0	0
Earnings (loss) before provision (benefit) for income taxes									24.8	(76.2)	(25.0)
Provision (benefit) for income taxes									15.3	(20.3)	(11.6)
Net earnings (loss)	(12.5)	4.7	18.5	(1.2)	(0.8)	(2.1)	(31.9)	(21.1)	9.5	(55.9)	(13.4)
Comprehensive income (loss)									8.0	(77.5)	(14.1)
Nortek [Member]
Condensed Financial Statements, Captions [Line Items]
Net Sales									0	0	0
Cost of products sold									0	0	0
Gross profit									0	0	0
Selling, general and administrative expense, net									44.7	40.4	26.9
Amortization of intangible assets									0	0	0
Operating earnings									(44.7)	(40.4)	(26.9)
Interest expense									(93.9)	(102.6)	(92.2)
Loss from debt retirement									(6.4)	(33.8)
Investment income									0	0	0
(Loss) income before charges and allocations to subsidiaries and equity in subsidiaries' earnings (loss) before income taxes									(145.0)	(176.8)	(119.1)
Charges and allocations to subsidiaries and equity in subsidiaries' earnings (loss) before income taxes									169.8	100.6	94.1
Earnings (loss) before provision (benefit) for income taxes									24.8	(76.2)	(25.0)
Provision (benefit) for income taxes									15.3	(20.3)	(11.6)
Net earnings (loss)									9.5	(55.9)	(13.4)
Comprehensive income (loss)									8.0	(77.5)	(14.1)
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net Sales									1,809.5	1,736.9	1,563.6
Cost of products sold									1,277.1	1,245.5	1,131.4
Gross profit									532.4	491.4	432.2
Selling, general and administrative expense, net									338.6	335.2	300.9
Amortization of intangible assets									41.9	42.3	33.7
Operating earnings									151.9	113.9	97.6
Interest expense									(2.2)	(1.9)	(1.9)
Loss from debt retirement									0	0
Investment income									0	0	0
(Loss) income before charges and allocations to subsidiaries and equity in subsidiaries' earnings (loss) before income taxes									149.7	112.0	95.7
Charges and allocations to subsidiaries and equity in subsidiaries' earnings (loss) before income taxes									(59.3)	(72.2)	(65.1)
Earnings (loss) before provision (benefit) for income taxes									90.4	39.8	30.6
Provision (benefit) for income taxes									34.2	14.6	8.2
Net earnings (loss)									56.2	25.2	22.4
Comprehensive income (loss)									56.6	20.3	21.7
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net Sales									711.4	693.4	504.5
Cost of products sold									601.8	612.0	429.1
Gross profit									109.6	81.4	75.4
Selling, general and administrative expense, net									85.2	89.2	72.1
Amortization of intangible assets									2.8	2.5	3.3
Operating earnings									21.6	(10.3)	0
Interest expense									(0.4)	(1.1)	(1.6)
Loss from debt retirement									0	0
Investment income									0.1	0.1	0.1
(Loss) income before charges and allocations to subsidiaries and equity in subsidiaries' earnings (loss) before income taxes									21.3	(11.3)	(1.5)
Charges and allocations to subsidiaries and equity in subsidiaries' earnings (loss) before income taxes									12.4	0.3	(0.4)
Earnings (loss) before provision (benefit) for income taxes									33.7	(11.0)	(1.9)
Provision (benefit) for income taxes									7.6	6.1	6.5
Net earnings (loss)									26.1	(17.1)	(8.4)
Comprehensive income (loss)									25.2	(21.6)	(7.7)
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net Sales									(319.6)	(289.8)	(168.8)
Cost of products sold									(318.0)	(289.7)	(168.7)
Gross profit									(1.6)	(0.1)	(0.1)
Selling, general and administrative expense, net									0	0	0
Amortization of intangible assets									(0.4)	0	0
Operating earnings									(1.2)	(0.1)	(0.1)
Interest expense									0	0	0
Loss from debt retirement									0	0
Investment income									0	0	0
(Loss) income before charges and allocations to subsidiaries and equity in subsidiaries' earnings (loss) before income taxes									(1.2)	(0.1)	(0.1)
Charges and allocations to subsidiaries and equity in subsidiaries' earnings (loss) before income taxes									(122.9)	(28.7)	(28.6)
Earnings (loss) before provision (benefit) for income taxes									(124.1)	(28.8)	(28.7)
Provision (benefit) for income taxes									(41.8)	(20.7)	(14.7)
Net earnings (loss)									(82.3)	(8.1)	(14.0)
Comprehensive income (loss)									$ (81.8)	$ 1.3	$ (14.0)