Operating Segments - Operating Segment Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 02, 2016	Sep. 27, 2015	Oct. 02, 2016	Sep. 27, 2015	Dec. 31, 2015
Segment Reporting Information [Line Items]
Depreciation expense	$ 11,600	$ 11,800	$ 35,300	$ 35,100
Amortization expense	23,808	25,669	75,603	78,090
Severance, restructuring, and acquisition integration costs	12,795	14,143	27,072	33,533
Segment assets	3,811,963		3,811,963		$ 3,290,602
Broadcast Solutions [Member]
Segment Reporting Information [Line Items]
Severance, restructuring, and acquisition integration costs	174	13,722	5,871	28,543
Enterprise Connectivity Solutions [Member]
Segment Reporting Information [Line Items]
Severance, restructuring, and acquisition integration costs	5,573	192	7,280	832
Industrial Connectivity Solutions [Member]
Segment Reporting Information [Line Items]
Severance, restructuring, and acquisition integration costs	4,746	118	7,982	3,054
Network Security Solutions [Member]
Segment Reporting Information [Line Items]
Severance, restructuring, and acquisition integration costs	0	57	29	1,102
Reportable Segment [Member]
Segment Reporting Information [Line Items]
Segment revenues	602,468	590,115	1,749,649	1,758,079
Affiliate revenues	2,157	2,064	6,209	6,514
Segment EBITDA	111,936	98,005	310,337	286,602
Depreciation expense	11,603	11,818	35,253	35,051
Amortization expense	23,808	25,669	75,603	78,090
Severance, restructuring, and acquisition integration costs	12,795	14,143	27,072	33,533
Purchase accounting effects of acquisitions	0	0	195	9,422
Deferred gross profit adjustments	1,359	11,328	5,412	46,426
Segment assets	946,966	966,102	946,966	966,102
Reportable Segment [Member] | Broadcast Solutions [Member]
Segment Reporting Information [Line Items]
Segment revenues	196,173	186,722	560,966	538,145
Affiliate revenues	46	42	644	24
Segment EBITDA	36,545	27,369	89,317	73,374
Depreciation expense	4,063	4,027	12,086	12,140
Amortization expense	10,955	12,354	37,306	37,375
Severance, restructuring, and acquisition integration costs	174	13,722	5,871	28,532
Purchase accounting effects of acquisitions			195	0
Deferred gross profit adjustments	283	419	1,391	2,789
Segment assets	314,020	346,271	314,020	346,271
Reportable Segment [Member] | Enterprise Connectivity Solutions [Member]
Segment Reporting Information [Line Items]
Segment revenues	156,658	155,148	452,951	458,756
Affiliate revenues	1,587	1,630	4,615	5,328
Segment EBITDA	27,294	25,705	80,605	75,506
Depreciation expense	3,210	3,156	10,028	9,550
Amortization expense	431	429	1,292	1,290
Severance, restructuring, and acquisition integration costs	5,573	192	7,280	843
Purchase accounting effects of acquisitions			0	0
Deferred gross profit adjustments	0	0	0	0
Segment assets	265,085	266,248	265,085	266,248
Reportable Segment [Member] | Industrial Connectivity Solutions [Member]
Segment Reporting Information [Line Items]
Segment revenues	149,847	147,702	438,746	461,549
Affiliate revenues	511	355	906	1,086
Segment EBITDA	23,649	23,225	73,700	76,078
Depreciation expense	2,738	2,810	8,165	8,530
Amortization expense	604	799	1,796	2,429
Severance, restructuring, and acquisition integration costs	4,746	118	7,982	3,054
Purchase accounting effects of acquisitions			0	267
Deferred gross profit adjustments	0	0	0	0
Segment assets	261,923	250,622	261,923	250,622
Reportable Segment [Member] | Industrial IT Solutions [Member]
Segment Reporting Information [Line Items]
Segment revenues	60,168	59,184	176,560	181,527
Affiliate revenues	13	37	44	68
Segment EBITDA	12,771	10,466	34,056	31,731
Depreciation expense	565	570	1,749	1,713
Amortization expense	1,501	1,480	4,517	4,369
Severance, restructuring, and acquisition integration costs	2,302	54	5,910	2
Purchase accounting effects of acquisitions			0	0
Deferred gross profit adjustments	0	0	0	0
Segment assets	62,828	61,441	62,828	61,441
Reportable Segment [Member] | Network Security Solutions [Member]
Segment Reporting Information [Line Items]
Segment revenues	39,622	41,359	120,426	118,102
Affiliate revenues	0	0	0	8
Segment EBITDA	11,677	11,240	32,659	29,913
Depreciation expense	1,027	1,255	3,225	3,118
Amortization expense	10,317	10,607	30,692	32,627
Severance, restructuring, and acquisition integration costs	0	57	29	1,102
Purchase accounting effects of acquisitions			0	9,155
Deferred gross profit adjustments	1,076	10,909	4,021	43,637
Segment assets	$ 43,110	$ 41,520	$ 43,110	$ 41,520