Revenue Disaggregation of Revenue by Geography (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Revenues	$ 320,451	$ 318,567	$ 303,379	$ 328,607	$ 315,523	$ 307,471	$ 312,282	$ 330,932	$ 1,271,004	$ 1,266,208	$ 1,400,040
EMEA [Member]
Disaggregation of Revenue [Line Items]
Revenues									132,763	130,530	134,363
Other foreign countries [Member]
Disaggregation of Revenue [Line Items]
Revenues									227,614	212,336	210,996
Foreign [Member]
Disaggregation of Revenue [Line Items]
Revenues									$ 360,377	$ 342,866	$ 345,359
UNITED STATES
Disaggregation of Revenue [Line Items]
Percent of total revenue									72.00%	73.00%	75.00%
Revenues									$ 910,627	$ 923,342	$ 1,054,681
International Sales [Domain]
Disaggregation of Revenue [Line Items]
Percent of total revenue									28.00%	27.00%	25.00%