Operating Segments - Operating Segment Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 01, 2017	Oct. 02, 2016	Oct. 01, 2017	Oct. 02, 2016	Dec. 31, 2016
Segment Reporting Information [Line Items]
Depreciation expense	$ 11,700	$ 11,600	$ 34,600	$ 35,300
Amortization expense	27,162	23,808	77,944	75,603
Severance, restructuring, and acquisition integration costs	16,679	12,795	32,839	27,072
Segment assets	3,704,848		3,704,848		$ 3,806,803
Broadcast Solutions
Segment Reporting Information [Line Items]
Severance, restructuring, and acquisition integration costs	3,056	174	4,434	5,871
Enterprise Solutions
Segment Reporting Information [Line Items]
Severance, restructuring, and acquisition integration costs	6,253	5,573	19,267	7,280
Industrial Solutions
Segment Reporting Information [Line Items]
Severance, restructuring, and acquisition integration costs	6,840	4,746	8,307	7,982
Reportable Segment
Segment Reporting Information [Line Items]
Segment revenues	621,745	602,468	1,783,759	1,749,649
Affiliate revenues	1,880	2,157	6,932	6,209
Segment EBITDA	117,531	111,936	320,868	310,337
Depreciation expense	11,683	11,603	34,594	35,253
Amortization expense	27,162	23,808	77,944	75,603
Severance, restructuring, and acquisition integration costs	16,679	12,795	32,839	27,072
Purchase accounting effects of acquisitions	2,922	0	4,089	195
Deferred gross profit adjustments	0	1,359	0	5,412
Segment assets	1,058,713	946,966	1,058,713	946,966
Reportable Segment | Broadcast Solutions
Segment Reporting Information [Line Items]
Segment revenues	193,753	196,173	550,420	560,966
Affiliate revenues	129	46	324	644
Segment EBITDA	35,671	36,545	90,681	89,317
Depreciation expense	4,088	4,063	12,095	12,086
Amortization expense	13,482	10,955	36,950	37,306
Severance, restructuring, and acquisition integration costs	3,056	174	4,434	5,871
Purchase accounting effects of acquisitions	2,922		4,089	195
Deferred gross profit adjustments		283		1,391
Segment assets	373,848	314,020	373,848	314,020
Reportable Segment | Enterprise Solutions
Segment Reporting Information [Line Items]
Segment revenues	167,089	156,658	473,504	452,951
Affiliate revenues	1,419	1,587	5,522	4,615
Segment EBITDA	26,409	27,294	77,310	80,605
Depreciation expense	2,740	3,210	8,034	10,028
Amortization expense	438	431	1,291	1,292
Severance, restructuring, and acquisition integration costs	6,253	5,573	19,267	7,280
Purchase accounting effects of acquisitions	0		0	0
Deferred gross profit adjustments		0		0
Segment assets	284,327	265,085	284,327	265,085
Reportable Segment | Industrial Solutions
Segment Reporting Information [Line Items]
Segment revenues	160,471	149,847	465,907	438,746
Affiliate revenues	332	511	994	906
Segment EBITDA	30,545	23,649	87,314	73,700
Depreciation expense	3,285	2,738	9,659	8,165
Amortization expense	646	604	1,928	1,796
Severance, restructuring, and acquisition integration costs	6,840	4,746	8,307	7,982
Purchase accounting effects of acquisitions	0		0	0
Deferred gross profit adjustments		0		0
Segment assets	291,984	261,923	291,984	261,923
Reportable Segment | Network Solutions
Segment Reporting Information [Line Items]
Segment revenues	100,432	99,790	293,928	296,986
Affiliate revenues	0	13	92	44
Segment EBITDA	24,906	24,448	65,563	66,715
Depreciation expense	1,570	1,592	4,806	4,974
Amortization expense	12,596	11,818	37,775	35,209
Severance, restructuring, and acquisition integration costs	530	2,302	831	5,939
Purchase accounting effects of acquisitions	0		0	0
Deferred gross profit adjustments		1,076		4,021
Segment assets	$ 108,554	$ 105,938	$ 108,554	$ 105,938