Guarantor Financial Statements - Condensed Consolidating Statement of Operations and Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 27, 2015	Jun. 28, 2014	Jun. 27, 2015	Jun. 28, 2014
Condensed Financial Statements, Captions [Line Items]
Net Sales	$ 703.9	$ 718.6	$ 1,276.6	$ 1,266.4
Cost of products sold	505.8	509.0	911.7	902.5
Gross profit	198.1	209.6	364.9	363.9
Selling, general and administrative expense, net	146.1	146.1	289.4	274.3
Non-cash impairment charges	1.2	80.4	1.2	80.4
Amortization of intangible assets	16.1	15.2	31.9	28.8
Operating earnings (loss)	34.7	(32.1)	42.4	(19.6)
Net interest expense	(24.9)	(26.6)	(52.1)	(50.7)
Loss from debt retirement	(14.8)	(1.8)	(14.8)	(1.8)
Loss before benefit from income taxes	(5.0)	(60.5)	(24.5)	(72.1)
Charges and allocations to subsidiaries and equity in subsidiaries' (loss) earnings before income taxes	0.0	0.0	0.0	0.0
(Loss) earnings before (benefit) provision for income taxes	(5.0)	(60.5)	(24.5)	(72.1)
(Benefit) provision for income taxes	(2.7)	(14.3)	(8.3)	(17.3)
Net loss	(2.3)	(46.2)	(16.2)	(54.8)
Currency translation adjustment	2.3	2.1	(3.8)	(0.4)
Total pension liability adjustments, net of tax	0.4	(0.3)	0.4	(0.3)
Other comprehensive income (loss)	2.7	1.8	(3.4)	(0.7)
Comprehensive income (loss)	0.4	(44.4)	(19.6)	(55.5)
Eliminations
Condensed Financial Statements, Captions [Line Items]
Net Sales	(133.9)	(148.9)	(231.7)	(252.4)
Cost of products sold	(133.0)	(148.5)	(231.5)	(250.3)
Gross profit	(0.9)	(0.4)	(0.2)	(2.1)
Selling, general and administrative expense, net	0.0	0.0	0.0	0.0
Non-cash impairment charges	0.0	0.0	0.0	0.0
Amortization of intangible assets	(0.2)	(0.2)	(0.4)	(0.4)
Operating earnings (loss)	(0.7)	(0.2)	0.2	(1.7)
Net interest expense	0.0	0.0	0.0	0.0
Loss from debt retirement	0.0	0.0	0.0	0.0
Loss before benefit from income taxes	(0.7)	(0.2)	0.2	(1.7)
Charges and allocations to subsidiaries and equity in subsidiaries' (loss) earnings before income taxes	(25.6)	36.9	(33.1)	25.9
(Loss) earnings before (benefit) provision for income taxes	(26.3)	36.7	(32.9)	24.2
(Benefit) provision for income taxes	(11.1)	9.4	(15.1)	3.1
Net loss	(15.2)	27.3	(17.8)	21.1
Currency translation adjustment	(2.3)	(2.0)	2.9	0.4
Total pension liability adjustments, net of tax	(0.3)	0.3	(0.3)	0.3
Other comprehensive income (loss)	(2.6)	(1.7)	2.6	0.7
Comprehensive income (loss)	(17.8)	25.6	(15.2)	21.8
Nortek | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
Net Sales	0.0	0.0	0.0	0.0
Cost of products sold	0.0	0.0	0.0	0.0
Gross profit	0.0	0.0	0.0	0.0
Selling, general and administrative expense, net	12.6	18.4	25.4	33.7
Non-cash impairment charges	0.0	0.0	0.0	0.0
Amortization of intangible assets	0.0	0.0	0.0	0.0
Operating earnings (loss)	(12.6)	(18.4)	(25.4)	(33.7)
Net interest expense	(24.0)	(25.8)	(50.3)	(49.7)
Loss from debt retirement	(14.8)	(1.8)	(14.8)	(1.8)
Loss before benefit from income taxes	(51.4)	(46.0)	(90.5)	(85.2)
Charges and allocations to subsidiaries and equity in subsidiaries' (loss) earnings before income taxes	46.4	(14.5)	66.0	13.1
(Loss) earnings before (benefit) provision for income taxes	(5.0)	(60.5)	(24.5)	(72.1)
(Benefit) provision for income taxes	(2.7)	(14.3)	(8.3)	(17.3)
Net loss	(2.3)	(46.2)	(16.2)	(54.8)
Currency translation adjustment	2.3	2.1	(3.8)	(0.4)
Total pension liability adjustments, net of tax	0.4	(0.3)	0.4	(0.3)
Other comprehensive income (loss)	2.7	1.8	(3.4)	(0.7)
Comprehensive income (loss)	0.4	(44.4)	(19.6)	(55.5)
Guarantor Subsidiaries | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
Net Sales	612.0	624.3	1,094.8	1,086.1
Cost of products sold	445.5	447.5	793.6	776.8
Gross profit	166.5	176.8	301.2	309.3
Selling, general and administrative expense, net	107.9	101.0	214.5	193.0
Non-cash impairment charges	0.2	70.1	0.2	70.1
Amortization of intangible assets	14.8	14.0	29.5	27.1
Operating earnings (loss)	43.6	(8.3)	57.0	19.1
Net interest expense	(0.9)	(0.8)	(1.8)	(0.9)
Loss from debt retirement	0.0	0.0	0.0	0.0
Loss before benefit from income taxes	42.7	(9.1)	55.2	18.2
Charges and allocations to subsidiaries and equity in subsidiaries' (loss) earnings before income taxes	(20.9)	(22.7)	(32.8)	(39.5)
(Loss) earnings before (benefit) provision for income taxes	21.8	(31.8)	22.4	(21.3)
(Benefit) provision for income taxes	7.9	(9.0)	9.3	(4.8)
Net loss	13.9	(22.8)	13.1	(16.5)
Currency translation adjustment	0.0	0.0	0.0	0.0
Total pension liability adjustments, net of tax	0.0	0.0	0.0	0.0
Other comprehensive income (loss)	0.0	0.0	0.0	0.0
Comprehensive income (loss)	13.9	(22.8)	13.1	(16.5)
Non-Guarantor Subsidiaries | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
Net Sales	225.8	243.2	413.5	432.7
Cost of products sold	193.3	210.0	349.6	376.0
Gross profit	32.5	33.2	63.9	56.7
Selling, general and administrative expense, net	25.6	26.7	49.5	47.6
Non-cash impairment charges	1.0	10.3	1.0	10.3
Amortization of intangible assets	1.5	1.4	2.8	2.1
Operating earnings (loss)	4.4	(5.2)	10.6	(3.3)
Net interest expense	0.0	0.0	0.0	(0.1)
Loss from debt retirement	0.0	0.0	0.0	0.0
Loss before benefit from income taxes	4.4	(5.2)	10.6	(3.4)
Charges and allocations to subsidiaries and equity in subsidiaries' (loss) earnings before income taxes	0.1	0.3	(0.1)	0.5
(Loss) earnings before (benefit) provision for income taxes	4.5	(4.9)	10.5	(2.9)
(Benefit) provision for income taxes	3.2	(0.4)	5.8	1.7
Net loss	1.3	(4.5)	4.7	(4.6)
Currency translation adjustment	2.3	2.0	(2.9)	(0.4)
Total pension liability adjustments, net of tax	0.3	(0.3)	0.3	(0.3)
Other comprehensive income (loss)	2.6	1.7	(2.6)	(0.7)
Comprehensive income (loss)	$ 3.9	$ (2.8)	$ 2.1	$ (5.3)