Operating Segments - Operating Segment Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 27, 2015	Sep. 28, 2014	Sep. 27, 2015	Sep. 28, 2014	Dec. 31, 2014
Segment Reporting Information [Line Items]
Segment revenues	$ 579,266	$ 610,774	$ 1,711,978	$ 1,699,355
Depreciation expense	11,800	10,700	35,100	31,600
Amortization of intangibles	25,669	15,203	78,090	42,739
Severance, restructuring, and acquisition integration costs	14,143	9,158	33,533	48,809
Segment assets	3,459,363		3,459,363		$ 3,262,827
Broadcast Solutions [Member]
Segment Reporting Information [Line Items]
Severance, restructuring, and acquisition integration costs	13,722	5,794	28,543	34,761
Enterprise Connectivity Solutions [Member]
Segment Reporting Information [Line Items]
Severance, restructuring, and acquisition integration costs	192	226	832	2,047
Industrial Connectivity Solutions [Member]
Segment Reporting Information [Line Items]
Severance, restructuring, and acquisition integration costs	118	2,106	3,054	10,250
Network Security Solutions [Member]
Segment Reporting Information [Line Items]
Severance, restructuring, and acquisition integration costs	57		1,102
Reportable Segment [Member]
Segment Reporting Information [Line Items]
Segment revenues	590,115	613,131	1,758,079	1,706,492
Affiliate revenues	2,067	2,872	6,508	8,708
Segment EBITDA	98,043	96,285	286,662	259,154
Depreciation expense	11,818	10,746	35,051	31,643
Amortization of intangibles	25,669	15,203	78,090	42,739
Severance, restructuring, and acquisition integration costs	14,143	9,158	33,533	48,809
Purchase accounting effects of acquisitions		858	9,422	9,873
Deferred gross profit adjustments	11,328	2,357	46,426	6,722
Segment assets	966,102	991,624	966,102	991,624
Reportable Segment [Member] | Broadcast Solutions [Member]
Segment Reporting Information [Line Items]
Segment revenues	228,097	256,587	661,098	675,350
Affiliate revenues	338	318	1,059	601
Segment EBITDA	34,880	38,450	95,726	95,939
Depreciation expense	4,261	3,856	12,819	11,346
Amortization of intangibles	12,647	13,020	38,256	37,963
Severance, restructuring, and acquisition integration costs	13,722	5,794	28,543	34,761
Purchase accounting effects of acquisitions				7,458
Deferred gross profit adjustments	419	2,357	2,789	6,722
Segment assets	401,405	433,063	401,405	433,063
Reportable Segment [Member] | Enterprise Connectivity Solutions [Member]
Segment Reporting Information [Line Items]
Segment revenues	113,773	115,349	335,803	345,015
Affiliate revenues	1,337	2,147	4,287	5,852
Segment EBITDA	18,232	17,730	53,214	51,572
Depreciation expense	2,922	3,134	8,871	10,633
Amortization of intangibles	136	162	409	497
Severance, restructuring, and acquisition integration costs	192	226	832	2,047
Purchase accounting effects of acquisitions				286
Segment assets	211,114	223,726	211,114	223,726
Reportable Segment [Member] | Industrial Connectivity Solutions [Member]
Segment Reporting Information [Line Items]
Segment revenues	147,702	171,105	461,549	508,667
Affiliate revenues	355	397	1,086	2,237
Segment EBITDA	23,225	26,487	76,078	79,631
Depreciation expense	2,810	3,150	8,530	7,992
Amortization of intangibles	799	266	2,429	802
Severance, restructuring, and acquisition integration costs	118	2,106	3,054	10,250
Purchase accounting effects of acquisitions			267	533
Segment assets	250,622	270,078	250,622	270,078
Reportable Segment [Member] | Industrial IT Solutions [Member]
Segment Reporting Information [Line Items]
Segment revenues	59,184	70,090	181,527	177,460
Affiliate revenues	37	10	68	18
Segment EBITDA	10,466	13,618	31,731	32,012
Depreciation expense	570	606	1,713	1,672
Amortization of intangibles	1,480	1,755	4,369	3,477
Severance, restructuring, and acquisition integration costs	54	1,032	2	1,751
Purchase accounting effects of acquisitions		858		1,596
Segment assets	61,441	$ 64,757	61,441	$ 64,757
Reportable Segment [Member] | Network Security Solutions [Member]
Segment Reporting Information [Line Items]
Segment revenues	41,359		118,102
Affiliate revenues			8
Segment EBITDA	11,240		29,913
Depreciation expense	1,255		3,118
Amortization of intangibles	10,607		32,627
Severance, restructuring, and acquisition integration costs	57		1,102
Purchase accounting effects of acquisitions			9,155
Deferred gross profit adjustments	10,909		43,637
Segment assets	$ 41,520		$ 41,520