Revenue From Contracts With Customers (Disaggregation of Revenue, By Geography) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disaggregation of Revenue [Line Items]
Total	$ 330,051	$ 356,346	$ 413,613	$ 359,864	$ 361,055	$ 392,615	$ 369,373	$ 285,846	$ 1,459,874	$ 1,408,889	$ 1,006,173
North America
Disaggregation of Revenue [Line Items]
Total									202,743
Germany
Disaggregation of Revenue [Line Items]
Total									111,259
Other including Eastern Europe/CIS
Disaggregation of Revenue [Line Items]
Total									296,917
China
Disaggregation of Revenue [Line Items]
Total									629,079
Japan
Disaggregation of Revenue [Line Items]
Total									87,619
Other
Disaggregation of Revenue [Line Items]
Total									127,251
Rest of World
Disaggregation of Revenue [Line Items]
Total									$ 5,006