Operating Segments - Reconciliation of Total Reportable Segments' Revenues and EBITDA to Consolidated Revenues and Consolidated Income from Continuing Operations Before Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 01, 2017	Oct. 02, 2016	Oct. 01, 2017	Oct. 02, 2016
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Consolidated Revenues	$ 621,745	$ 601,109	$ 1,783,759	$ 1,744,237
Amortization of intangibles	(27,162)	(23,808)	(77,944)	(75,603)
Severance, restructuring, and acquisition integration costs	(16,679)	(12,795)	(32,839)	(27,072)
Depreciation expense	(11,700)	(11,600)	(34,600)	(35,300)
Operating income	60,791	61,980	174,609	165,185
Interest expense, net	(19,385)	(23,513)	(66,424)	(71,958)
Loss on debt extinguishment	(51,594)	0	(52,441)	0
Income before taxes	(10,188)	38,467	55,744	93,227
Reportable Segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total Segment Revenues	621,745	602,468	1,783,759	1,749,649
Deferred revenue adjustments	0	(1,359)	0	(5,412)
Consolidated Revenues	621,745	601,109	1,783,759	1,744,237
Total Segment EBITDA	117,531	111,936	320,868	310,337
Amortization of intangibles	(27,162)	(23,808)	(77,944)	(75,603)
Severance, restructuring, and acquisition integration costs	(16,679)	(12,795)	(32,839)	(27,072)
Depreciation expense	(11,683)	(11,603)	(34,594)	(35,253)
Purchase accounting effects related to acquisitions	(2,922)	0	(4,089)	(195)
Deferred gross profit adjustments	0	(1,359)	0	(5,412)
Income from equity method investment	2,551	586	5,835	1,077
Eliminations
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating income	$ (845)	$ (977)	$ (2,628)	$ (2,694)