Geographic Information (Revenue by Geographic Locations) (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($) Reportable_Segments	Jun. 30, 2018 USD ($)
Segment Reporting [Abstract]
Number of reportable segments | Reportable_Segments			1
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 1,252,329	$ 1,029,348	$ 1,252,329	$ 1,029,348
Operating revenue	144,275	124,626	287,199	232,856
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	395,564	395,748	395,564	395,748
Operating revenue	45,068	48,400	91,143	98,302
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	5,963	6,210	5,963	6,210
Operating revenue	1,258	1,456	2,309	3,056
Latin America
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	16,743	19,179	16,743	19,179
Operating revenue	4,974	5,161	8,996	10,555
Australia
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	1,989	1,640	1,989	1,640
Operating revenue	8,730	8,740	17,355	18,227
Singapore
Revenues from External Customers and Long-Lived Assets [Line Items]
Pre-Existing Revenue	2,300
Long-lived assets	18,357	17,926	18,357	17,926
Operating revenue	2,015	1,924	4,144	4,140
New Zealand
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	665	272	665	272
Operating revenue	488	526	1,010	1,013
India
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	730,286	507,404	730,286	507,404
Operating revenue	73,909	51,351	146,817	83,354
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	23,536	25,555	23,536	25,555
Operating revenue	3,634	3,841	7,421	7,872
INDONESIA
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	85	97	85	97
Operating revenue	2,627	1,828	5,172	3,369
PHILIPPINES
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	536	912	536	912
Operating revenue	1,347	1,245	2,497	2,593
UNITED ARAB EMIRATES
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	58,605	$ 54,405	$ 58,605	$ 54,405
Indian Led [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue	$ 156,700