Guarantor Financial Statements (Condensed Consolidating Cash Flow Statement) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash Flows from operating activities:
Net cash (used in) provided by operating activities	$ 164.2	$ 80.9	$ 46.9
Cash Flows from investing activities:
Capital expenditures	(24.1)	(21.1)	(19.8)
Net cash paid for businesses acquired	(2.6)	(30.9)	(285.2)
Investment in joint venture	0	(5.3)	0
Proceeds from the sale of property and equipment	3.0	1.3	0.4
Change in restricted cash and marketable securities	0.2	0.2	1.2
Intercompany dividend paid by (received from) subsidiaries	0		0
Other, net	0	0.1	0
Net cash used in investing activities	(23.5)	(55.7)	(303.4)
Cash Flows from financing activities:
Increase in borrowings	34.6	82.8	133.1
Payment of borrowings	(84.0)	(140.3)	(149.1)
Net proceeds from the sale of the 10% Senior Unsecured Notes due 2018	0	0	250.0
Net proceeds from the sale of the 8.5% Senior Notes due 2021	251.7	500.0	0
Redemption of the Term Loan Facility	(251.7)	0	0
Net proceeds from borrowings under the Term Loan Facility	0	348.2	0
Redemption of the 11% Senior Secured Notes due 2013	0	(753.3)	0
Fees paid in connection with debt facilities	(5.9)	(59.6)	(9.5)
Net proceeds from equity transactions	1.2	(2.7)	0
Intercompany capital contributions		0
Long-term intercompany advances and loans	0	0	0
Other, net	(0.1)	0.2	0.1
Net cash (used in) provided by financing activities	(54.2)	(24.7)	224.6
Net change in unrestricted cash and cash equivalents	86.5	0.5	(31.9)
Unrestricted cash and cash equivalents at the beginning of the period	58.2	57.7	89.6
Unrestricted cash and cash equivalents at the end of the period	144.7	58.2	57.7
Nortek [Member]
Cash Flows from operating activities:
Net cash (used in) provided by operating activities	(141.4)	(121.6)	(145.7)
Cash Flows from investing activities:
Capital expenditures	(1.8)	(0.1)	(0.3)
Net cash paid for businesses acquired	(2.6)	(5.8)	(76.1)
Investment in joint venture		0
Proceeds from the sale of property and equipment	0	0.7	0
Change in restricted cash and marketable securities	0.1	0	0.1
Intercompany dividend paid by (received from) subsidiaries	0		10.8
Other, net	0.1	0	0.1
Net cash used in investing activities	(4.2)	(5.2)	(65.4)
Cash Flows from financing activities:
Increase in borrowings	30.0	50.0	90.1
Payment of borrowings	(57.7)	(102.6)	(95.0)
Net proceeds from the sale of the 10% Senior Unsecured Notes due 2018			250.0
Net proceeds from the sale of the 8.5% Senior Notes due 2021	251.7	500.0
Redemption of the Term Loan Facility	(251.7)
Net proceeds from borrowings under the Term Loan Facility		348.2
Redemption of the 11% Senior Secured Notes due 2013		(753.3)
Fees paid in connection with debt facilities	(5.9)	(59.6)	(9.5)
Net proceeds from equity transactions	1.2	(2.7)
Intercompany capital contributions		(3.0)
Long-term intercompany advances and loans	255.2	151.5	(52.1)
Other, net	(0.1)	0.1	0
Net cash (used in) provided by financing activities	222.7	128.6	183.5
Net change in unrestricted cash and cash equivalents	77.1	1.8	(27.6)
Unrestricted cash and cash equivalents at the beginning of the period	17.8	16.0	43.6
Unrestricted cash and cash equivalents at the end of the period	94.9	17.8	16.0
Guarantor Subsidiaries [Member]
Cash Flows from operating activities:
Net cash (used in) provided by operating activities	280.1	185.5	177.7
Cash Flows from investing activities:
Capital expenditures	(16.2)	(14.8)	(13.4)
Net cash paid for businesses acquired	0	(25.1)	(209.1)
Investment in joint venture		(5.3)
Proceeds from the sale of property and equipment	2.5	0.5	0
Change in restricted cash and marketable securities	0.1	0.2	0.7
Intercompany dividend paid by (received from) subsidiaries	6.5		4.2
Other, net	0	0	(0.2)
Net cash used in investing activities	(7.1)	(44.5)	(217.8)
Cash Flows from financing activities:
Increase in borrowings	0	5.3	0
Payment of borrowings	(2.4)	(6.9)	(2.2)
Net proceeds from the sale of the 10% Senior Unsecured Notes due 2018			0
Net proceeds from the sale of the 8.5% Senior Notes due 2021	0	0
Redemption of the Term Loan Facility	0
Net proceeds from borrowings under the Term Loan Facility		0
Redemption of the 11% Senior Secured Notes due 2013		0
Fees paid in connection with debt facilities	0	0	0
Net proceeds from equity transactions	0	0
Intercompany capital contributions		2.7
Long-term intercompany advances and loans	(266.8)	(154.2)	52.1
Other, net	0	0.1	0.1
Net cash (used in) provided by financing activities	(269.2)	(153.0)	50.0
Net change in unrestricted cash and cash equivalents	3.8	(12.0)	9.9
Unrestricted cash and cash equivalents at the beginning of the period	9.3	21.3	11.4
Unrestricted cash and cash equivalents at the end of the period	13.1	9.3	21.3
Non-Guarantor Subsidiaries [Member]
Cash Flows from operating activities:
Net cash (used in) provided by operating activities	25.5	17.0	14.9
Cash Flows from investing activities:
Capital expenditures	(6.1)	(6.2)	(6.1)
Net cash paid for businesses acquired	0	0	0
Investment in joint venture		0
Proceeds from the sale of property and equipment	0.5	0.1	0.4
Change in restricted cash and marketable securities	0	0	0.4
Intercompany dividend paid by (received from) subsidiaries	(6.5)		(15.0)
Other, net	(0.1)	0.1	0.1
Net cash used in investing activities	(12.2)	(6.0)	(20.2)
Cash Flows from financing activities:
Increase in borrowings	4.6	27.5	43.0
Payment of borrowings	(23.9)	(30.8)	(51.9)
Net proceeds from the sale of the 10% Senior Unsecured Notes due 2018			0
Net proceeds from the sale of the 8.5% Senior Notes due 2021	0	0
Redemption of the Term Loan Facility	0
Net proceeds from borrowings under the Term Loan Facility		0
Redemption of the 11% Senior Secured Notes due 2013		0
Fees paid in connection with debt facilities	0	0	0
Net proceeds from equity transactions	0	0
Intercompany capital contributions		0.3
Long-term intercompany advances and loans	11.6	2.7	0
Other, net	0	0	0
Net cash (used in) provided by financing activities	(7.7)	(0.3)	(8.9)
Net change in unrestricted cash and cash equivalents	5.6	10.7	(14.2)
Unrestricted cash and cash equivalents at the beginning of the period	31.1	20.4	34.6
Unrestricted cash and cash equivalents at the end of the period	$ 36.7	$ 31.1	$ 20.4