Geographic Information (Revenue by Geographic Locations) (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) Reportable_Segments	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Segment Reporting [Abstract]
Number of reportable segments | Reportable_Segments			1
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 1,188,047		$ 1,188,047		$ 1,227,685
Operating revenue	111,312	$ 144,275	249,188	$ 287,199
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	392,070		392,070		395,225
Operating revenue	41,714	45,068	83,626	91,143
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	6,552		6,552		7,012
Operating revenue	1,119	1,258	2,233	2,309
Latin America
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	13,056		13,056		17,176
Operating revenue	3,577	4,974	7,814	8,996
Australia
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	3,194		3,194		3,541
Operating revenue	7,399	8,730	15,585	17,355
Singapore
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	18,099		18,099		18,282
Operating revenue	795	2,015	2,048	4,144
New Zealand
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	499		499		578
Operating revenue	382	488	818	1,010
India
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	671,994		671,994		700,986
Operating revenue	52,635	73,909	126,550	146,817
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	22,017		22,017		24,508
Operating revenue	3,249	3,634	6,530	7,421
INDONESIA
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	164		164		117
Operating revenue	179	2,627	2,321	5,172
PHILIPPINES
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	688		688		729
Operating revenue	253	1,347	1,529	2,497
UNITED ARAB EMIRATES
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	59,714		59,714		$ 59,531
Operating revenue	10	225	134	335
Indian Led [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue	$ 53,200	$ 78,900	$ 131,100	$ 156,700