Reportable Segments - Reconciliation of Total Reportable Segments' Revenues and EBITDA to Consolidated Revenues and Consolidated Income Before Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 28, 2020	Jun. 30, 2019	Jun. 28, 2020	Jun. 30, 2019
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Segment revenues	$ 424,811	$ 548,352	$ 888,337	$ 1,048,492
Amortization of Intangible Assets	(16,017)	(19,068)	(32,202)	(37,232)
Depreciation expense	(10,300)	(9,900)	(20,600)	(20,000)
Severance, restructuring, and acquisition integration costs	4,472	2,519	8,091	2,519
Operating income	17,130	58,775	46,838	106,265
Interest expense, net	(14,257)	(13,961)	(27,581)	(27,949)
Total non-operating pension benefit	700	537	1,399	1,140
Consolidated income from continuing operations before taxes	3,573	45,351	20,656	79,456
Reportable Segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Segment revenues	424,811	548,352	888,337	1,048,492
Total Segment EBITDA	48,680	91,315	108,919	167,614
Amortization of Intangible Assets	(16,017)	(19,068)	(32,202)	(37,232)
Depreciation expense	(10,332)	(9,908)	(20,614)	(20,011)
Severance, restructuring, and acquisition integration costs	4,472	2,519	8,091	2,519
Amortization of software development intangible assets	(386)	(63)	(716)	(122)
Purchase accounting effects related to acquisitions	105	718	125	718
Intersegment Eliminations [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Segment Elimination	$ (238)	$ (264)	$ (333)	$ (747)