Revenue from Contracts with Customers Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 29, 2019	Jun. 30, 2018	Jun. 29, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Revenues	$ 1,431,061	$ 1,367,727	$ 2,820,938	$ 2,660,588
Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenues	1,272,605	1,207,140	2,550,798	2,379,770
Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Revenues	158,456	160,587	270,140	280,818
Domestic Segment
Disaggregation of Revenue [Line Items]
Revenues	1,266,112	1,202,064	2,496,942	2,337,160
Domestic Segment | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenues	1,124,513	1,062,878	2,260,495	2,091,373
Domestic Segment | Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Revenues	141,599	139,186	236,447	245,787
International Segment [Member]
Disaggregation of Revenue [Line Items]
Revenues	164,949	165,663	323,996	323,428
International Segment [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenues	148,092	144,262	290,303	288,397
International Segment [Member] | Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Revenues	16,857	21,401	33,693	35,031
Revenue, Licensed Software, Net [Member]
Disaggregation of Revenue [Line Items]
Revenues	197,113	172,388	351,590	307,207
Revenue, Licensed Software, Net [Member] | Domestic Segment
Disaggregation of Revenue [Line Items]
Revenues	181,061	161,220	321,506	285,314
Revenue, Licensed Software, Net [Member] | International Segment [Member]
Disaggregation of Revenue [Line Items]
Revenues	16,052	11,168	30,084	21,893
Revenue, Technology Resale, Net [Member]
Disaggregation of Revenue [Line Items]
Revenues	60,735	75,257	116,275	138,633
Revenue, Technology Resale, Net [Member] | Domestic Segment
Disaggregation of Revenue [Line Items]
Revenues	54,851	61,789	104,009	120,038
Revenue, Technology Resale, Net [Member] | International Segment [Member]
Disaggregation of Revenue [Line Items]
Revenues	5,884	13,468	12,266	18,595
Revenue, Subscriptions, Net [Member]
Disaggregation of Revenue [Line Items]
Revenues	89,770	82,951	174,061	159,587
Revenue, Subscriptions, Net [Member] | Domestic Segment
Disaggregation of Revenue [Line Items]
Revenues	83,573	76,419	161,275	146,271
Revenue, Subscriptions, Net [Member] | International Segment [Member]
Disaggregation of Revenue [Line Items]
Revenues	6,197	6,532	12,786	13,316
Revenue, Professional Services, Net [Member]
Disaggregation of Revenue [Line Items]
Revenues	485,307	447,318	975,746	888,586
Revenue, Professional Services, Net [Member] | Domestic Segment
Disaggregation of Revenue [Line Items]
Revenues	429,910	387,540	867,139	767,384
Revenue, Professional Services, Net [Member] | International Segment [Member]
Disaggregation of Revenue [Line Items]
Revenues	55,397	59,778	108,607	121,202
Revenue, Managed Services, Net [Member]
Disaggregation of Revenue [Line Items]
Revenues	297,651	285,552	602,044	553,857
Revenue, Managed Services, Net [Member] | Domestic Segment
Disaggregation of Revenue [Line Items]
Revenues	268,560	261,787	545,885	507,932
Revenue, Managed Services, Net [Member] | International Segment [Member]
Disaggregation of Revenue [Line Items]
Revenues	29,091	23,765	56,159	45,925
Revenue, Support and Maintenance Services, Net [Member]
Disaggregation of Revenue [Line Items]
Revenues	276,411	278,956	553,374	563,520
Revenue, Support and Maintenance Services, Net [Member] | Domestic Segment
Disaggregation of Revenue [Line Items]
Revenues	225,602	229,779	452,083	464,015
Revenue, Support and Maintenance Services, Net [Member] | International Segment [Member]
Disaggregation of Revenue [Line Items]
Revenues	50,809	49,177	101,291	99,505
Revenue, Reimbursement Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenues	24,074	25,305	47,848	49,198
Revenue, Reimbursement Revenue [Member] | Domestic Segment
Disaggregation of Revenue [Line Items]
Revenues	22,555	23,530	45,045	46,206
Revenue, Reimbursement Revenue [Member] | International Segment [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 1,519	$ 1,775	$ 2,803	$ 2,992