Guarantor Financial Statements - Condensed Consolidating Cash Flow Statement (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 27, 2015	Jun. 28, 2014
Cash Flows from operating activities:
Net cash (used in) provided by operating activities	$ (80.9)	$ (60.5)
Cash Flows from investing activities:
Capital expenditures	(20.0)	(18.3)
Net cash paid for businesses acquired	(51.8)	(254.9)
Intercompany dividends		0.0
Intercompany contributions	0.0	0.0
Proceeds from the sale of property and equipment	0.1	1.6
Change in restricted cash and marketable securities	0.1	0.3
Other, net	(0.6)	(1.5)
Net cash used in investing activities	(72.2)	(272.8)
Cash Flows from financing activities:
Proceeds from ABL and other borrowings	284.1	141.5
Payment of ABL and other borrowings	(158.0)	(48.1)
Redemption of the 10% Senior Notes due 2018, including redemption premium	(262.5)	0.0
Net proceeds from borrowings under the senior secured term loan facility due 2020	261.8	349.1
Redemption of the senior secured term loan facility due 2017	0.0	(93.0)
Fees paid in connection with debt facilities	(2.7)	(5.9)
Net use from equity transactions	(1.9)	(3.7)
Excess tax benefit on share-based awards	0.0	3.8
Long-term intercompany advances and loans	0.0	0.0
Other, net	0.1	0.0
Net cash provided by financing activities	120.9	343.7
Net change in unrestricted cash and cash equivalents	(32.2)	10.4
Unrestricted cash and cash equivalents at the beginning of the period	58.4	80.9
Unrestricted cash and cash equivalents at the end of the period	26.2	91.3
Nortek | Reportable Legal Entities
Cash Flows from operating activities:
Net cash (used in) provided by operating activities	(92.5)	(89.7)
Cash Flows from investing activities:
Capital expenditures	(1.1)	(4.9)
Net cash paid for businesses acquired	0.0	(184.5)
Intercompany dividends		0.0
Intercompany contributions	(0.9)	(0.3)
Proceeds from the sale of property and equipment	0.0	0.0
Change in restricted cash and marketable securities	0.0	0.1
Other, net	0.0	0.0
Net cash used in investing activities	(2.0)	(189.6)
Cash Flows from financing activities:
Proceeds from ABL and other borrowings	283.0	140.0
Payment of ABL and other borrowings	(155.1)	(45.1)
Redemption of the 10% Senior Notes due 2018, including redemption premium	(262.5)
Net proceeds from borrowings under the senior secured term loan facility due 2020	261.8	349.1
Redemption of the senior secured term loan facility due 2017		(93.0)
Fees paid in connection with debt facilities	(2.7)	(5.9)
Net use from equity transactions	(1.9)	(3.7)
Excess tax benefit on share-based awards		3.8
Long-term intercompany advances and loans	(41.3)	(51.6)
Other, net	0.1	0.0
Net cash provided by financing activities	81.4	293.6
Net change in unrestricted cash and cash equivalents	(13.1)	14.3
Unrestricted cash and cash equivalents at the beginning of the period	17.5	23.2
Unrestricted cash and cash equivalents at the end of the period	4.4	37.5
Guarantor Subsidiaries | Reportable Legal Entities
Cash Flows from operating activities:
Net cash (used in) provided by operating activities	11.7	17.2
Cash Flows from investing activities:
Capital expenditures	(15.7)	(11.1)
Net cash paid for businesses acquired	(51.8)	0.0
Intercompany dividends		15.5
Intercompany contributions	0.0	0.0
Proceeds from the sale of property and equipment	0.1	1.1
Change in restricted cash and marketable securities	0.1	0.1
Other, net	(0.8)	(1.5)
Net cash used in investing activities	(68.1)	4.1
Cash Flows from financing activities:
Proceeds from ABL and other borrowings	0.0	0.0
Payment of ABL and other borrowings	(1.6)	(1.4)
Redemption of the 10% Senior Notes due 2018, including redemption premium	0.0
Net proceeds from borrowings under the senior secured term loan facility due 2020	0.0	0.0
Redemption of the senior secured term loan facility due 2017		0.0
Fees paid in connection with debt facilities	0.0	0.0
Net use from equity transactions	0.0	0.0
Excess tax benefit on share-based awards		0.0
Long-term intercompany advances and loans	53.4	(25.8)
Other, net	0.0	0.0
Net cash provided by financing activities	51.8	(27.2)
Net change in unrestricted cash and cash equivalents	(4.6)	(5.9)
Unrestricted cash and cash equivalents at the beginning of the period	5.1	20.0
Unrestricted cash and cash equivalents at the end of the period	0.5	14.1
Non-Guarantor Subsidiaries | Reportable Legal Entities
Cash Flows from operating activities:
Net cash (used in) provided by operating activities	(0.1)	12.0
Cash Flows from investing activities:
Capital expenditures	(3.2)	(2.3)
Net cash paid for businesses acquired	0.0	(70.4)
Intercompany dividends		(15.5)
Intercompany contributions	0.9	0.3
Proceeds from the sale of property and equipment	0.0	0.5
Change in restricted cash and marketable securities	0.0	0.1
Other, net	0.2	0.0
Net cash used in investing activities	(2.1)	(87.3)
Cash Flows from financing activities:
Proceeds from ABL and other borrowings	1.1	1.5
Payment of ABL and other borrowings	(1.3)	(1.6)
Redemption of the 10% Senior Notes due 2018, including redemption premium	0.0
Net proceeds from borrowings under the senior secured term loan facility due 2020	0.0	0.0
Redemption of the senior secured term loan facility due 2017		0.0
Fees paid in connection with debt facilities	0.0	0.0
Net use from equity transactions	0.0	0.0
Excess tax benefit on share-based awards		0.0
Long-term intercompany advances and loans	(12.1)	77.4
Other, net	0.0	0.0
Net cash provided by financing activities	(12.3)	77.3
Net change in unrestricted cash and cash equivalents	(14.5)	2.0
Unrestricted cash and cash equivalents at the beginning of the period	35.8	37.7
Unrestricted cash and cash equivalents at the end of the period	$ 21.3	$ 39.7