Geographic Information (Revenue by Geographic Locations) (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) reportableSegment	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Segment Reporting [Abstract]
Number of reportable segments | reportableSegment			1
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue	$ 154,305	$ 147,233	$ 403,493	$ 434,432
Long-lived assets	1,203,582		1,203,582		$ 1,227,685
India
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue	93,403	77,145	219,953	223,962
Long-lived assets	615,859		615,859		700,986
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue	40,124	45,038	123,750	136,181
Long-lived assets	390,008		390,008		395,225
Australia
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue	8,187	8,643	23,773	25,997
Long-lived assets	3,254		3,254		3,541
Latin America
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue	3,633	5,400	11,447	14,397
Long-lived assets	20,038		20,038		17,176
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue	3,306	3,584	9,836	11,005
Long-lived assets	22,493		22,493		24,508
Indonesia
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue	394	2,004	2,714	7,177
Long-lived assets	144		144		117
Singapore
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue	896	1,260	2,944	5,404
Long-lived assets	12,378		12,378		18,282
Philippines
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue	213	2,185	1,742	4,682
Long-lived assets	684		684		729
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue	1,122	1,207	3,355	3,516
Long-lived assets	78,635		78,635		7,012
New Zealand
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue	459	494	1,277	1,504
Long-lived assets	489		489		578
United Arab Emirates
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue	2,568	273	2,702	607
Long-lived assets	59,600		59,600		$ 59,531
Indian Led
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue	$ 96,800	$ 82,100	$ 227,900	$ 238,800