Segment Information (Revenue By Geographic Area) (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 166,928	$ 356,600	$ 356,585	$ 672,278	$ 1,089,297
Long-lived assets	574,588			574,588		$ 664,949
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	95,100		255,427	423,376	805,704
Long-lived assets	411,974			411,974		489,189
International [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	71,828		$ 101,158	248,902	$ 283,593
Long-lived assets	$ 162,614			$ 162,614		$ 175,760