Restructuring - (Restructuring Plans) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring	$ 19,581
Restructuring accruals	6,957	$ 45,095
Operational Initiatives for Cloud-based Subscription Business, Strategic Focus and Efficiencies
Restructuring Cost and Reserve [Line Items]
Restructuring	22,200	2,500	$ 53,700
Operational Initiatives Designed to Improve Infrastructure Scalability and Cost Saving Efficiencies
Restructuring Cost and Reserve [Line Items]
Restructuring			8,100
Consolidation of Leased Facilities
Restructuring Cost and Reserve [Line Items]
Restructuring	2,700	$ 14,200	$ 9,700
Employee Severance
Restructuring Cost and Reserve [Line Items]
Restructuring accruals	7,000
Employee Severance | Operational Initiatives for Cloud-based Subscription Business, Strategic Focus and Efficiencies
Restructuring Cost and Reserve [Line Items]
Restructuring	$ 19,600