BUSINESS SEGMENTS - Segment Information (Detail) - USD ($) $ in Millions		3 Months Ended																12 Months Ended
		Dec. 28, 2018		Sep. 28, 2018	[2]	Jun. 29, 2018	[3]	Mar. 30, 2018	[4]	Dec. 29, 2017		Sep. 29, 2017	[6]	Jun. 30, 2017	[7]	Mar. 31, 2017	[8]	Dec. 28, 2018	Dec. 29, 2017	Dec. 30, 2016
Segment Reporting Information [Line Items]
Net sales		$ 2,119.1	[1]	$ 2,179.0		$ 2,137.9		$ 1,964.2		$ 2,013.8	[5]	$ 2,016.4		$ 2,001.4		$ 1,895.8		$ 8,400.2	$ 7,927.4	$ 7,622.8
Operating income (losses)		(87.3)	[1]	$ (89.5)		$ (71.3)		$ (61.6)		(80.6)	[5]	$ (80.8)		$ (82.6)		$ (68.9)		(309.7)	(312.9)	(295.5)
Depreciation																		31.7	28.2	27.9
Amortization of intangible assets																		37.3	36.1	37.6
Total assets		4,653.1								4,252.2								4,653.1	4,252.2
Capital expenditures																		42.4	41.1	32.6
Network and Security Solutions [Member]
Segment Reporting Information [Line Items]
Net sales																		4,347.0	4,114.4	4,083.8
Operating income (losses)																		(272.2)	(262.6)	(275.8)
Depreciation																		3.8	3.1	3.2
Amortization of intangible assets																		17.0	14.4	14.1
Total assets		2,319.3								1,947.1								2,319.3	1,947.1	1,974.0
Capital expenditures																		8.7	3.7	3.4
Electrical and Electronic Solutions [Member]
Segment Reporting Information [Line Items]
Net sales																		2,342.7	2,225.5	2,103.2
Operating income (losses)																		(132.3)	(114.3)	(97.5)
Depreciation																		2.4	2.4	2.7
Amortization of intangible assets																		7.0	8.4	8.5
Total assets		1,097.4								1,068.3								1,097.4	1,068.3	983.6
Capital expenditures																		2.0	1.9	2.9
Utility Power Solutions [Member]
Segment Reporting Information [Line Items]
Net sales																		1,710.5	1,587.5	1,435.8
Operating income (losses)																		(75.4)	(73.1)	(56.7)
Depreciation																		3.6	3.9	4.2
Amortization of intangible assets																		13.3	13.3	15.0
Total assets		905.5								871.4								905.5	871.4	821.9
Capital expenditures																		6.7	1.7	2.5
Corporate [Member]
Segment Reporting Information [Line Items]
Net sales	[9]																	0.0	0.0	0.0
Operating income (losses)	[9]																	170.2	137.1	134.5
Depreciation	[9]																	21.9	18.8	17.8
Amortization of intangible assets	[9]																	0.0	0.0	0.0
Total assets	[9]	330.9								365.4								330.9	365.4	313.9
Capital expenditures	[9]																	25.0	33.8	23.8
Continuing Operations [Member]
Segment Reporting Information [Line Items]
Net sales																		8,400.2	7,927.4	7,622.8
Operating income (losses)																		(309.7)	(312.9)	(295.5)
Depreciation																		31.7	28.2	27.9
Amortization of intangible assets																		37.3	36.1	37.6
Total assets		$ 4,653.1								$ 4,252.2								4,653.1	4,252.2	4,093.4
Capital expenditures																		$ 42.4	$ 41.1	$ 32.6

[1] In the fourth quarter of 2018, "Operating income" includes $8.7 million of intangible asset amortization and $0.2 million of U.K. facility relocation costs. "Income before income taxes" includes a $4.6 million loss on extinguishment of debt.

[2] In the third quarter of 2018, "Operating income" includes $9.6 million of intangible asset amortization, a restructuring charge of $0.2 million, $0.3 million of acquisition and integration costs and $0.2 million of U.K. facility relocation costs.

[3] In the second quarter of 2018, "Operating income" includes $9.7 million of intangible asset amortization, a restructuring charge of $9.2 million, $2.3 million of acquisition and integration costs, $2.6 million of CEO retirement agreement expense and $0.4 million of U.K. facility relocation costs.

[4] In the first quarter of 2018, "Operating income" includes $9.3 million of intangible asset amortization, $0.3 million of acquisition and integration costs and $0.2 million of U.K. facility relocation costs.

[5] In the fourth quarter of 2017, "Operating income" includes $9.0 million of intangible asset amortization, $1.5 million of acquisition and integration costs and an intangible asset impairment charge of $5.7 million.

[6] In the third quarter of 2017, "Operating income" includes $9.1 million of intangible asset amortization and $0.8 million of acquisition and integration costs.

[7] In the second quarter of 2017, "Operating income" includes $9.0 million of intangible asset amortization.

[8] In the first quarter of 2017, "Operating income" includes $9.0 million of intangible asset amortization.

[9] Corporate "Total assets" primarily consists of cash and cash equivalents, deferred tax assets, and corporate fixed assets.