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, 2014	Sep. 27, 2014	Jun. 28, 2014	Mar. 29, 2014	Dec. 31, 2013	Sep. 28, 2013	Jun. 29, 2013	Mar. 30, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Condensed Financial Statements, Captions [Line Items]
Net Sales	$ 636.8	$ 642.9	$ 718.6	$ 547.8	$ 548.9	$ 589.2	$ 630.7	$ 519.1	$ 2,546.1	$ 2,287.9	$ 2,201.3
Cost of products sold									1,805.0	1,624.6	1,560.9
Gross profit	187.2	190.0	209.6	154.3	161.2	173.7	187.2	141.2	741.1	663.3	640.4
Selling, general and administrative expense, net	141.8	141.7	146.1	128.2	133.3	128.0	133.2	125.3	557.8	519.8	468.5
Asset impairment charges	0	0	80.4	0	4.3	0	0	0	80.4	4.3	0
Amortization of intangible assets									60.0	51.3	44.3
Operating earnings (loss)	29.1	33.4	(32.1)	12.5	10.4	32.5	40.4	4.6	42.9	87.9	127.6
Net interest expense									(105.6)	(99.3)	(96.4)
Loss from debt retirement									(2.3)	0	(6.4)
(Loss) income before charges and allocations to subsidiaries and equity in subsidiaries' (loss) earnings before income taxes									(65.0)	(11.4)	24.8
Charges and allocations to subsidiaries and equity in subsidiaries' (loss) earnings before income taxes									0	0	0
(Loss) earnings before (benefit) provision for income taxes									(65.0)	(11.4)	24.8
(Benefit) provision for income taxes									(19.4)	(3.1)	15.3
Net (loss) earnings	4.6	4.6	(46.2)	(8.6)	(8.9)	4.2	11.5	(15.1)	(45.6)	(8.3)	9.5
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Currency translation adjustment									(7.9)	(3.0)	1.4
Total pension liability adjustments, net of tax									(11.5)	9.0	(2.9)
Other comprehensive income (loss)									(19.4)	6.0	(1.5)
Comprehensive (loss) income									(65.0)	(2.3)	8.0
Reportable Legal Entities [Member] | 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									63.5	60.3	44.7
Asset impairment charges									0	0
Amortization of intangible assets									0	0	0
Operating earnings (loss)									(63.5)	(60.3)	(44.7)
Net interest expense									(102.6)	(96.2)	(93.9)
Loss from debt retirement									(2.3)		(6.4)
(Loss) income before charges and allocations to subsidiaries and equity in subsidiaries' (loss) earnings before income taxes									(168.4)	(156.5)	(145.0)
Charges and allocations to subsidiaries and equity in subsidiaries' (loss) earnings before income taxes									103.4	145.1	169.8
(Loss) earnings before (benefit) provision for income taxes									(65.0)	(11.4)	24.8
(Benefit) provision for income taxes									(19.4)	(3.1)	15.3
Net (loss) earnings									(45.6)	(8.3)	9.5
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Currency translation adjustment									(7.9)	(3.0)	1.4
Total pension liability adjustments, net of tax									(11.5)	9.0	(2.9)
Other comprehensive income (loss)									(19.4)	6.0	(1.5)
Comprehensive (loss) income									(65.0)	(2.3)	8.0
Reportable Legal Entities [Member] | Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net Sales									2,155.1	1,938.4	1,809.5
Cost of products sold									1,536.3	1,385.8	1,277.1
Gross profit									618.8	552.6	532.4
Selling, general and administrative expense, net									394.5	369.3	338.6
Asset impairment charges									70.1	4.3
Amortization of intangible assets									55.2	49.2	41.9
Operating earnings (loss)									99.0	129.8	151.9
Net interest expense									(2.9)	(3.0)	(2.2)
Loss from debt retirement									0		0
(Loss) income before charges and allocations to subsidiaries and equity in subsidiaries' (loss) earnings before income taxes									96.1	126.8	149.7
Charges and allocations to subsidiaries and equity in subsidiaries' (loss) earnings before income taxes									(73.1)	(67.8)	(59.3)
(Loss) earnings before (benefit) provision for income taxes									23.0	59.0	90.4
(Benefit) provision for income taxes									6.3	23.9	34.2
Net (loss) earnings									16.7	35.1	56.2
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Currency translation adjustment									0	0	0
Total pension liability adjustments, net of tax									(2.6)	3.0	0.4
Other comprehensive income (loss)									(2.6)	3.0	0.4
Comprehensive (loss) income									14.1	38.1	56.6
Reportable Legal Entities [Member] | Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net Sales									854.3	729.4	711.4
Cost of products sold									730.6	619.0	601.8
Gross profit									123.7	110.4	109.6
Selling, general and administrative expense, net									99.8	90.2	85.2
Asset impairment charges									10.3	0
Amortization of intangible assets									5.6	2.9	2.8
Operating earnings (loss)									8.0	17.3	21.6
Net interest expense									(0.1)	(0.1)	(0.3)
Loss from debt retirement									0		0
(Loss) income before charges and allocations to subsidiaries and equity in subsidiaries' (loss) earnings before income taxes									7.9	17.2	21.3
Charges and allocations to subsidiaries and equity in subsidiaries' (loss) earnings before income taxes									0.2	1.2	12.4
(Loss) earnings before (benefit) provision for income taxes									8.1	18.4	33.7
(Benefit) provision for income taxes									10.1	6.6	7.6
Net (loss) earnings									(2.0)	11.8	26.1
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Currency translation adjustment									(6.7)	(3.0)	1.8
Total pension liability adjustments, net of tax									(3.5)	(1.0)	(2.7)
Other comprehensive income (loss)									(10.2)	(4.0)	(0.9)
Comprehensive (loss) income									(12.2)	7.8	25.2
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net Sales									(463.3)	(379.9)	(319.6)
Cost of products sold									(461.9)	(380.2)	(318.0)
Gross profit									(1.4)	0.3	(1.6)
Selling, general and administrative expense, net									0	0	0
Asset impairment charges									0	0
Amortization of intangible assets									(0.8)	(0.8)	(0.4)
Operating earnings (loss)									(0.6)	1.1	(1.2)
Net interest expense									0	0	0
Loss from debt retirement									0		0
(Loss) income before charges and allocations to subsidiaries and equity in subsidiaries' (loss) earnings before income taxes									(0.6)	1.1	(1.2)
Charges and allocations to subsidiaries and equity in subsidiaries' (loss) earnings before income taxes									(30.5)	(78.5)	(122.9)
(Loss) earnings before (benefit) provision for income taxes									(31.1)	(77.4)	(124.1)
(Benefit) provision for income taxes									(16.4)	(30.5)	(41.8)
Net (loss) earnings									(14.7)	(46.9)	(82.3)
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Currency translation adjustment									6.7	3.0	(1.8)
Total pension liability adjustments, net of tax									6.1	(2.0)	2.3
Other comprehensive income (loss)									12.8	1.0	0.5
Comprehensive (loss) income									$ (1.9)	$ (45.9)	$ (81.8)