Operating Segments - Operating Segment Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2018	Jul. 02, 2017	Jul. 01, 2018	Jul. 02, 2017	Dec. 31, 2017
Segment Reporting Information [Line Items]
Depreciation expense	$ 12,000	$ 11,500	$ 23,900	$ 22,900
Amortization of intangibles	25,039	27,113	49,457	50,782
Severance, restructuring, and acquisition integration costs	24,928	9,560	45,322	16,160
Segment assets	3,639,419		3,639,419		$ 3,840,613
Enterprise Solutions
Segment Reporting Information [Line Items]
Severance, restructuring, and acquisition integration costs	22,887	9,111	37,421	14,392
Industrial Solutions
Segment Reporting Information [Line Items]
Severance, restructuring, and acquisition integration costs	2,041	449	7,901	1,768
Reportable Segment
Segment Reporting Information [Line Items]
Segment revenues	671,441	610,633	1,278,864	1,162,014
Affiliate revenues	1,513	1,103	2,588	3,162
Segment EBITDA	123,506	110,522	227,384	203,892
Depreciation expense	12,026	11,528	23,891	22,911
Amortization of intangibles	25,039	27,113	49,457	50,782
Amortization of software development intangible assets	488	0	724	0
Severance, restructuring, and acquisition integration costs	24,928	9,560	45,322	16,160
Purchase accounting effects of acquisitions	1,036	1,167	1,538	1,167
Deferred revenue adjustments	2,802	0	4,660	0
Segment assets	1,196,219	1,022,068	1,196,219	1,022,068
Reportable Segment | Enterprise Solutions
Segment Reporting Information [Line Items]
Segment revenues	399,695	348,804	750,685	663,082
Affiliate revenues	1,496	1,080	2,542	3,113
Segment EBITDA	70,281	56,441	127,733	105,964
Depreciation expense	7,153	6,753	14,373	13,301
Amortization of intangibles	11,809	13,882	22,979	24,321
Amortization of software development intangible assets	488		724
Severance, restructuring, and acquisition integration costs	22,887	9,111	37,421	14,392
Purchase accounting effects of acquisitions	1,036	1,167	1,538	1,167
Deferred revenue adjustments	2,802		4,660
Segment assets	759,334	634,930	759,334	634,930
Reportable Segment | Industrial Solutions
Segment Reporting Information [Line Items]
Segment revenues	271,746	261,829	528,179	498,932
Affiliate revenues	17	23	46	49
Segment EBITDA	53,225	54,081	99,651	97,928
Depreciation expense	4,873	4,775	9,518	9,610
Amortization of intangibles	13,230	13,231	26,478	26,461
Amortization of software development intangible assets	0		0
Severance, restructuring, and acquisition integration costs	2,041	449	7,901	1,768
Purchase accounting effects of acquisitions	0	0	0	0
Deferred revenue adjustments	0		0
Segment assets	$ 436,885	$ 387,138	$ 436,885	$ 387,138