Revenue Disaggregation of Revenue by Geography (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Revenues	$ 315,523	$ 307,471	$ 312,282	$ 330,932	$ 340,378	$ 327,169	$ 360,460	$ 372,033	$ 1,266,208	$ 1,400,040	$ 1,292,613
EMEA [Member]
Disaggregation of Revenue [Line Items]
Revenues									130,530	134,363	119,934
Other foreign countries [Member]
Disaggregation of Revenue [Line Items]
Revenues									212,336	210,996	192,640
Foreign [Member]
Disaggregation of Revenue [Line Items]
Revenues									$ 342,866	$ 345,359	$ 312,574
UNITED STATES
Disaggregation of Revenue [Line Items]
Percent of total revenue									73.00%	75.00%	76.00%
Revenues									$ 923,342	$ 1,054,681	$ 980,039
International Sales [Domain]
Disaggregation of Revenue [Line Items]
Percent of total revenue									27.00%	25.00%	24.00%