Guarantor Financial Statements (Condensed Consolidating Statement of Operations and Comprehensive Income (Loss)) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 29, 2013	Jun. 30, 2012	Jun. 29, 2013	Jun. 30, 2012
Condensed Financial Statements, Captions [Line Items]
Net Sales	$ 630.7	$ 615.7	$ 1,149.8	$ 1,138.5
Cost of products sold (COGS)	441.6	431.9	819.2	808.7
Gross profit	189.1	183.8	330.6	329.8
Selling, general and administrative expense, net (SG&A)	135.1	119.1	260.7	229.2
Amortization of intangible assets	13.6	11.0	24.9	22.0
Operating earnings	40.4	53.7	45.0	78.6
Interest expense	(24.8)	(24.0)	(49.4)	(48.5)
Investment income	0.1	0.1	0.1	0.1
Earnings (loss) before provision (benefit) for income taxes	15.7	29.8	(4.3)	30.2
Charges and allocations to subsidiaries and equity in subsidiaries' earnings (loss) before income taxes	0	0	0	0
Earnings (loss) before provision (benefit) for income taxes	15.7	29.8	(4.3)	30.2
Provision (benefit) for income taxes	4.2	11.3	(0.7)	12.9
Net earnings (loss)	11.5	18.5	(3.6)	17.3
Comprehensive (loss) income	9.9	16.0	(8.2)	16.7
Nortek [Member]
Condensed Financial Statements, Captions [Line Items]
Net Sales	0	0	0	0
Cost of products sold (COGS)	0	0	0	0
Gross profit	0	0	0	0
Selling, general and administrative expense, net (SG&A)	16.1	10.1	33.0	17.9
Amortization of intangible assets	0	0	0	0
Operating earnings	(16.1)	(10.1)	(33.0)	(17.9)
Interest expense	(24.2)	(23.4)	(48.0)	(47.0)
Investment income	0	0	0	0
Earnings (loss) before provision (benefit) for income taxes	(40.3)	(33.5)	(81.0)	(64.9)
Charges and allocations to subsidiaries and equity in subsidiaries' earnings (loss) before income taxes	56.0	63.3	76.7	95.1
Earnings (loss) before provision (benefit) for income taxes	15.7	29.8	(4.3)	30.2
Provision (benefit) for income taxes	4.2	11.3	(0.7)	12.9
Net earnings (loss)	11.5	18.5	(3.6)	17.3
Comprehensive (loss) income	9.9	16.0	(8.2)	16.7
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net Sales	544.8	508.6	978.7	930.2
Cost of products sold (COGS)	384.3	355.7	702.2	657.0
Gross profit	160.5	152.9	276.5	273.2
Selling, general and administrative expense, net (SG&A)	95.7	86.5	181.4	168.8
Amortization of intangible assets	13.1	10.3	23.9	20.6
Operating earnings	51.7	56.1	71.2	83.8
Interest expense	(0.6)	(0.5)	(1.3)	(1.2)
Investment income	0	0	0	0
Earnings (loss) before provision (benefit) for income taxes	51.1	55.6	69.9	82.6
Charges and allocations to subsidiaries and equity in subsidiaries' earnings (loss) before income taxes	(18.7)	(15.0)	(34.9)	(29.3)
Earnings (loss) before provision (benefit) for income taxes	32.4	40.6	35.0	53.3
Provision (benefit) for income taxes	8.1	15.8	8.2	20.6
Net earnings (loss)	24.3	24.8	26.8	32.7
Comprehensive (loss) income	24.3	24.8	26.9	32.7
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net Sales	192.9	198.7	364.9	364.4
Cost of products sold (COGS)	162.2	165.9	308.6	305.8
Gross profit	30.7	32.8	56.3	58.6
Selling, general and administrative expense, net (SG&A)	23.3	22.5	46.3	42.5
Amortization of intangible assets	0.7	0.7	1.4	1.4
Operating earnings	6.7	9.6	8.6	14.7
Interest expense	0	(0.1)	(0.1)	(0.3)
Investment income	0.1	0.1	0.1	0.1
Earnings (loss) before provision (benefit) for income taxes	6.8	9.6	8.6	14.5
Charges and allocations to subsidiaries and equity in subsidiaries' earnings (loss) before income taxes	0.3	0.1	0.5	0.2
Earnings (loss) before provision (benefit) for income taxes	7.1	9.7	9.1	14.7
Provision (benefit) for income taxes	3.1	3.7	4.0	6.7
Net earnings (loss)	4.0	6.0	5.1	8.0
Comprehensive (loss) income	2.1	3.3	0	7.5
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net Sales	(107.0)	(91.6)	(193.8)	(156.1)
Cost of products sold (COGS)	(104.9)	(89.7)	(191.6)	(154.1)
Gross profit	(2.1)	(1.9)	(2.2)	(2.0)
Selling, general and administrative expense, net (SG&A)	0	0	0	0
Amortization of intangible assets	(0.2)	0	(0.4)	0
Operating earnings	(1.9)	(1.9)	(1.8)	(2.0)
Interest expense	0	0	0	0
Investment income	0	0	0	0
Earnings (loss) before provision (benefit) for income taxes	(1.9)	(1.9)	(1.8)	(2.0)
Charges and allocations to subsidiaries and equity in subsidiaries' earnings (loss) before income taxes	(37.6)	(48.4)	(42.3)	(66.0)
Earnings (loss) before provision (benefit) for income taxes	(39.5)	(50.3)	(44.1)	(68.0)
Provision (benefit) for income taxes	(11.2)	(19.5)	(12.2)	(27.3)
Net earnings (loss)	(28.3)	(30.8)	(31.9)	(40.7)
Comprehensive (loss) income	$ (26.4)	$ (28.1)	$ (26.9)	$ (40.2)