Segment Information (Company's information by geographic area) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 400,936	$ 413,133
Long-lived assets	1,513,282	1,605,365	$ 1,605,365
UNITED STATES
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	333,609	303,576
Long-lived assets	1,210,392		1,288,077
Other Countries [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	67,327	$ 109,557
Long-lived assets	$ 302,890		$ 317,288