Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 29, 2019	Jun. 30, 2020	Jun. 29, 2019
Disaggregation of Revenue [Line Items]
Revenues	$ 1,330,349	$ 1,431,061	$ 2,742,090	$ 2,820,938
Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenues	1,253,253	1,272,605	2,572,212	2,550,798
Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Revenues	77,096	158,456	169,878	270,140
Domestic Segment
Disaggregation of Revenue [Line Items]
Revenues	1,168,213	1,266,112	2,414,628	2,496,942
Domestic Segment | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenues	1,101,797	1,124,513	2,267,312	2,260,495
Domestic Segment | Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Revenues	66,416	141,599	147,316	236,447
International Segment [Member]
Disaggregation of Revenue [Line Items]
Revenues	162,136	164,949	327,462	323,996
International Segment [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenues	151,456	148,092	304,900	290,303
International Segment [Member] | Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Revenues	10,680	16,857	22,562	33,693
Sales Revenue, Licensed Software, Net [Member]
Disaggregation of Revenue [Line Items]
Revenues	152,162	197,113	310,194	351,590
Sales Revenue, Licensed Software, Net [Member] | Domestic Segment
Disaggregation of Revenue [Line Items]
Revenues	138,950	181,061	285,447	321,506
Sales Revenue, Licensed Software, Net [Member] | International Segment [Member]
Disaggregation of Revenue [Line Items]
Revenues	13,212	16,052	24,747	30,084
Sales Revenue, Technology Resale, Net [Member]
Disaggregation of Revenue [Line Items]
Revenues	42,117	60,735	93,604	116,275
Sales Revenue, Technology Resale, Net [Member] | Domestic Segment
Disaggregation of Revenue [Line Items]
Revenues	36,376	54,851	80,825	104,009
Sales Revenue, Technology Resale, Net [Member] | International Segment [Member]
Disaggregation of Revenue [Line Items]
Revenues	5,741	5,884	12,779	12,266
Sales Revenue, Subscriptions, Net [Member]
Disaggregation of Revenue [Line Items]
Revenues	92,052	89,770	186,437	174,061
Sales Revenue, Subscriptions, Net [Member] | Domestic Segment
Disaggregation of Revenue [Line Items]
Revenues	85,281	83,573	172,217	161,275
Sales Revenue, Subscriptions, Net [Member] | International Segment [Member]
Disaggregation of Revenue [Line Items]
Revenues	6,771	6,197	14,220	12,786
Sales Revenue, Professional Services, Net [Member]
Disaggregation of Revenue [Line Items]
Revenues	461,082	485,307	972,428	975,746
Sales Revenue, Professional Services, Net [Member] | Domestic Segment
Disaggregation of Revenue [Line Items]
Revenues	409,848	429,910	862,632	867,139
Sales Revenue, Professional Services, Net [Member] | International Segment [Member]
Disaggregation of Revenue [Line Items]
Revenues	51,234	55,397	109,796	108,607
Sales Revenue, Managed Services, Net [Member]
Disaggregation of Revenue [Line Items]
Revenues	307,158	297,651	616,512	602,044
Sales Revenue, Managed Services, Net [Member] | Domestic Segment
Disaggregation of Revenue [Line Items]
Revenues	275,679	268,560	555,415	545,885
Sales Revenue, Managed Services, Net [Member] | International Segment [Member]
Disaggregation of Revenue [Line Items]
Revenues	31,479	29,091	61,097	56,159
Sales Revenue, Support and Maintenance Services, Net [Member]
Disaggregation of Revenue [Line Items]
Revenues	274,036	276,411	547,717	553,374
Sales Revenue, Support and Maintenance Services, Net [Member] | Domestic Segment
Disaggregation of Revenue [Line Items]
Revenues	220,301	225,602	443,717	452,083
Sales Revenue, Support and Maintenance Services, Net [Member] | International Segment [Member]
Disaggregation of Revenue [Line Items]
Revenues	53,735	50,809	104,000	101,291
Sales Revenue, Reimbursement Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenues	1,742	24,074	15,198	47,848
Sales Revenue, Reimbursement Revenue [Member] | Domestic Segment
Disaggregation of Revenue [Line Items]
Revenues	1,778	22,555	14,375	45,045
Sales Revenue, Reimbursement Revenue [Member] | International Segment [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ (36)	$ 1,519	$ 823	$ 2,803