Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Disaggregation of Revenue [Line Items]
Revenues	$ 1,387,778	$ 1,411,741
Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenues	1,306,717	1,318,959
Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Revenues	81,061	92,782
Domestic Segment
Disaggregation of Revenue [Line Items]
Revenues	1,221,992	1,246,415
Domestic Segment | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenues	1,152,849	1,165,515
Domestic Segment | Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Revenues	69,143	80,900
International Segment [Member]
Disaggregation of Revenue [Line Items]
Revenues	165,786	165,326
International Segment [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenues	153,868	153,444
International Segment [Member] | Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Revenues	11,918	11,882
Revenue, Licensed Software, Net [Member]
Disaggregation of Revenue [Line Items]
Revenues	161,661	158,032
Revenue, Licensed Software, Net [Member] | Domestic Segment
Disaggregation of Revenue [Line Items]
Revenues	148,833	146,497
Revenue, Licensed Software, Net [Member] | International Segment [Member]
Disaggregation of Revenue [Line Items]
Revenues	12,828	11,535
Revenue, Technology Resale, Net [Member]
Disaggregation of Revenue [Line Items]
Revenues	45,672	51,487
Revenue, Technology Resale, Net [Member] | Domestic Segment
Disaggregation of Revenue [Line Items]
Revenues	37,891	44,449
Revenue, Technology Resale, Net [Member] | International Segment [Member]
Disaggregation of Revenue [Line Items]
Revenues	7,781	7,038
Revenue, Subscriptions, Net [Member]
Disaggregation of Revenue [Line Items]
Revenues	99,812	94,385
Revenue, Subscriptions, Net [Member] | Domestic Segment
Disaggregation of Revenue [Line Items]
Revenues	95,383	86,936
Revenue, Subscriptions, Net [Member] | International Segment [Member]
Disaggregation of Revenue [Line Items]
Revenues	4,429	7,449
Revenue, Professional Services, Net [Member]
Disaggregation of Revenue [Line Items]
Revenues	494,422	511,346
Revenue, Professional Services, Net [Member] | Domestic Segment
Disaggregation of Revenue [Line Items]
Revenues	434,162	452,784
Revenue, Professional Services, Net [Member] | International Segment [Member]
Disaggregation of Revenue [Line Items]
Revenues	60,260	58,562
Revenue, Managed Services, Net [Member]
Disaggregation of Revenue [Line Items]
Revenues	317,376	309,354
Revenue, Managed Services, Net [Member] | Domestic Segment
Disaggregation of Revenue [Line Items]
Revenues	282,076	279,736
Revenue, Managed Services, Net [Member] | International Segment [Member]
Disaggregation of Revenue [Line Items]
Revenues	35,300	29,618
Revenue, Support and Maintenance Services, Net [Member]
Disaggregation of Revenue [Line Items]
Revenues	263,324	273,681
Revenue, Support and Maintenance Services, Net [Member] | Domestic Segment
Disaggregation of Revenue [Line Items]
Revenues	217,499	223,416
Revenue, Support and Maintenance Services, Net [Member] | International Segment [Member]
Disaggregation of Revenue [Line Items]
Revenues	45,825	50,265
Revenue, Reimbursement Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenues	5,511	13,456
Revenue, Reimbursement Revenue [Member] | Domestic Segment
Disaggregation of Revenue [Line Items]
Revenues	6,148	12,597
Revenue, Reimbursement Revenue [Member] | International Segment [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ (637)	$ 859