Guarantor Financial Statements (Condensed Consolidating Statement of Operations and Comprehensive Income (Loss)) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012
Condensed Financial Statements, Captions [Line Items]
Net Sales	$ 589.2	$ 557.4	$ 1,739.0	$ 1,695.9
Cost of products sold	414.1	399.0	1,233.3	1,207.7
Gross profit	175.1	158.4	505.7	488.2
Selling, general and administrative expense, net	129.4	113.6	390.1	342.8
Amortization of intangible assets	13.2	11.0	38.1	33.0
Operating earnings	32.5	33.8	77.5	112.4
Interest expense	(24.8)	(23.7)	(74.2)	(72.2)
Investment income	0	0.1	0.1	0.2
Earnings before provision for income taxes	7.7	10.2	3.4	40.4
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	7.7	10.2	3.4	40.4
Provision for income taxes	3.5	5.5	2.8	18.4
Net earnings	4.2	4.7	0.6	22.0
Comprehensive (loss) income	7.0	7.0	(1.2)	23.7
Nortek [Member]
Condensed Financial Statements, Captions [Line Items]
Net Sales	0	0	0	0
Cost of products sold	0	0	0	0
Gross profit	0	0	0	0
Selling, general and administrative expense, net	13.1	11.5	46.1	29.4
Amortization of intangible assets	0	0	0	0
Operating earnings	(13.1)	(11.5)	(46.1)	(29.4)
Interest expense	(24.2)	(23.1)	(72.2)	(70.1)
Investment income	0	0	0	0
Earnings before provision for income taxes	(37.3)	(34.6)	(118.3)	(99.5)
Charges and allocations to subsidiaries and equity in subsidiaries' earnings (loss) before income taxes	45.0	44.8	121.7	139.9
Earnings (loss) before provision (benefit) for income taxes	7.7	10.2	3.4	40.4
Provision for income taxes	3.5	5.5	2.8	18.4
Net earnings	4.2	4.7	0.6	22.0
Comprehensive (loss) income	7.0	7.0	(1.2)	23.7
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net Sales	510.6	461.9	1,489.3	1,392.1
Cost of products sold	365.2	328.9	1,067.4	985.9
Gross profit	145.4	133.0	421.9	406.2
Selling, general and administrative expense, net	94.1	81.8	275.5	250.6
Amortization of intangible assets	12.7	10.5	36.6	31.1
Operating earnings	38.6	40.7	109.8	124.5
Interest expense	(0.6)	(0.5)	(1.9)	(1.7)
Investment income	0	0	0	0
Earnings before provision for income taxes	38.0	40.2	107.9	122.8
Charges and allocations to subsidiaries and equity in subsidiaries' earnings (loss) before income taxes	(16.4)	(12.8)	(51.3)	(42.1)
Earnings (loss) before provision (benefit) for income taxes	21.6	27.4	56.6	80.7
Provision for income taxes	7.4	7.7	15.6	28.3
Net earnings	14.2	19.7	41.0	52.4
Comprehensive (loss) income	14.2	19.9	41.1	52.6
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net Sales	185.8	178.6	550.7	543.0
Cost of products sold	156.2	152.2	464.8	458.0
Gross profit	29.6	26.4	85.9	85.0
Selling, general and administrative expense, net	22.2	20.3	68.5	62.8
Amortization of intangible assets	0.7	0.7	2.1	2.1
Operating earnings	6.7	5.4	15.3	20.1
Interest expense	0	(0.1)	(0.1)	(0.4)
Investment income	0	0.1	0.1	0.2
Earnings before provision for income taxes	6.7	5.4	15.3	19.9
Charges and allocations to subsidiaries and equity in subsidiaries' earnings (loss) before income taxes	0.3	11.8	0.8	12.0
Earnings (loss) before provision (benefit) for income taxes	7.0	17.2	16.1	31.9
Provision for income taxes	3.8	4.1	7.8	10.8
Net earnings	3.2	13.1	8.3	21.1
Comprehensive (loss) income	6.0	15.2	6.0	22.7
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net Sales	(107.2)	(83.1)	(301.0)	(239.2)
Cost of products sold	(107.3)	(82.1)	(298.9)	(236.2)
Gross profit	0.1	(1.0)	(2.1)	(3.0)
Selling, general and administrative expense, net	0	0	0	0
Amortization of intangible assets	(0.2)	(0.2)	(0.6)	(0.2)
Operating earnings	0.3	(0.8)	(1.5)	(2.8)
Interest expense	0	0	0	0
Investment income	0	0	0	0
Earnings before provision for income taxes	0.3	(0.8)	(1.5)	(2.8)
Charges and allocations to subsidiaries and equity in subsidiaries' earnings (loss) before income taxes	(28.9)	(43.8)	(71.2)	(109.8)
Earnings (loss) before provision (benefit) for income taxes	(28.6)	(44.6)	(72.7)	(112.6)
Provision for income taxes	(11.2)	(11.8)	(23.4)	(39.1)
Net earnings	(17.4)	(32.8)	(49.3)	(73.5)
Comprehensive (loss) income	$ (20.2)	$ (35.1)	$ (47.1)	$ (75.3)