Operating Segments - Operating Segment Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 28, 2015	Jun. 29, 2014	Jun. 28, 2015	Jun. 29, 2014	Dec. 31, 2014
Segment Reporting Information [Line Items]
Segment revenues	$ 585,755	$ 600,891	$ 1,132,712	$ 1,088,581
Depreciation expense	11,700	11,400	23,200	20,900
Amortization expense	25,917	15,795	52,421	27,536
Severance, restructuring, and acquisition integration costs	4,907	38,208	19,390	39,651
Segment assets	3,502,643		3,502,643		$ 3,262,827
Broadcast Solutions [Member]
Segment Reporting Information [Line Items]
Severance, restructuring, and acquisition integration costs	3,283	27,524	14,821	28,967
Enterprise Connectivity Solutions [Member]
Segment Reporting Information [Line Items]
Severance, restructuring, and acquisition integration costs	83	1,821	640	1,821
Industrial Connectivity Solutions [Member]
Segment Reporting Information [Line Items]
Severance, restructuring, and acquisition integration costs	1,163	8,144	2,936	8,144
Network Security Solutions [Member]
Segment Reporting Information [Line Items]
Severance, restructuring, and acquisition integration costs	378		1,045
Reportable Segment [Member]
Segment Reporting Information [Line Items]
Segment revenues	598,513	605,054	1,167,964	1,093,361
Affiliate revenues	2,127	2,203	4,441	5,836
Segment EBITDA	100,345	89,253	188,619	162,869
Depreciation expense	11,692	11,400	23,233	20,897
Amortization expense	25,917	15,795	52,421	27,536
Severance, restructuring, and acquisition integration costs	4,907	38,208	19,390	39,651
Purchase accounting effects of acquisitions		8,163	9,422	9,015
Deferred gross profit adjustments	13,440	3,915	35,098	4,365
Segment assets	1,005,497	1,010,546	1,005,497	1,010,546
Reportable Segment [Member] | Broadcast Solutions [Member]
Segment Reporting Information [Line Items]
Segment revenues	219,415	252,278	433,001	418,763
Affiliate revenues	380	84	721	283
Segment EBITDA	31,614	31,318	60,846	57,489
Depreciation expense	4,373	4,609	8,558	7,490
Amortization expense	12,889	14,424	25,609	24,943
Severance, restructuring, and acquisition integration costs	3,283	27,524	14,821	28,967
Purchase accounting effects of acquisitions		7,148		7,458
Deferred gross profit adjustments	(924)	3,915	2,370	4,365
Segment assets	410,194	419,814	410,194	419,814
Reportable Segment [Member] | Enterprise Connectivity Solutions [Member]
Segment Reporting Information [Line Items]
Segment revenues	117,335	121,272	222,030	229,666
Affiliate revenues	1,330	1,628	2,950	3,704
Segment EBITDA	21,101	19,667	34,982	33,842
Depreciation expense	2,947	3,799	5,949	7,499
Amortization expense	135	167	273	335
Severance, restructuring, and acquisition integration costs	83	1,821	640	1,821
Purchase accounting effects of acquisitions		147		286
Segment assets	222,015	236,860	222,015	236,860
Reportable Segment [Member] | Industrial Connectivity Solutions [Member]
Segment Reporting Information [Line Items]
Segment revenues	160,875	178,244	313,847	337,562
Affiliate revenues	407	485	731	1,841
Segment EBITDA	28,680	29,462	52,853	53,144
Depreciation expense	2,869	2,458	5,720	4,842
Amortization expense	807	271	1,630	536
Severance, restructuring, and acquisition integration costs	1,163	8,144	2,936	8,144
Purchase accounting effects of acquisitions		250	267	533
Segment assets	267,448	282,874	267,448	282,874
Reportable Segment [Member] | Industrial IT Solutions [Member]
Segment Reporting Information [Line Items]
Segment revenues	61,270	53,260	122,343	107,370
Affiliate revenues	10	6	31	8
Segment EBITDA	10,178	8,806	21,265	18,394
Depreciation expense	584	534	1,143	1,066
Amortization expense	1,479	933	2,889	1,722
Severance, restructuring, and acquisition integration costs		719	(52)	719
Purchase accounting effects of acquisitions		618		738
Segment assets	63,599	$ 70,998	63,599	$ 70,998
Reportable Segment [Member] | Network Security Solutions [Member]
Segment Reporting Information [Line Items]
Segment revenues	39,618		76,743
Affiliate revenues			8
Segment EBITDA	8,772		18,673
Depreciation expense	919		1,863
Amortization expense	10,607		22,020
Severance, restructuring, and acquisition integration costs	378		1,045
Purchase accounting effects of acquisitions			9,155
Deferred gross profit adjustments	14,364		32,728
Segment assets	$ 42,241		$ 42,241