Geographic Information (Details) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2020 USD ($)	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2020 USD ($) product_service_group	Dec. 31, 2020 USD ($) segment	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Revenues from External Customers and Long-Lived Assets [Line Items]
Number of operating segments														3	1
Number of reportable segments | segment															1
Operating revenue	$ 222,116	$ 154,305	$ 111,312	$ 137,876	$ 146,183	$ 147,233	$ 144,275	$ 142,924	$ 136,327	$ 128,643	$ 124,626	$ 108,230	$ 625,609			$ 580,615	$ 497,826
Long-lived assets	1,207,955				1,227,684				1,183,567				1,207,955	$ 1,207,955	$ 1,207,955	1,227,684	1,183,567
India
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue													378,660			300,678	196,372
Long-lived assets	698,936				700,986				672,699				698,936	698,936	698,936	700,986	672,699
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue													166,320			182,530	196,984
Long-lived assets	381,782				395,225				390,551				381,782	381,782	381,782	395,225	390,551
Australia
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue													33,846			33,268	35,770
Long-lived assets	3,581				3,541				1,485				3,581	3,581	3,581	3,541	1,485
Latin America
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue													14,801			19,755	19,866
Long-lived assets	13,723				17,176				16,348				13,723	13,723	13,723	17,176	16,348
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue													13,145			14,695	15,387
Long-lived assets	22,900				24,508				23,880				22,900	22,900	22,900	24,508	23,880
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue													4,383			4,805	5,611
Long-lived assets	6,930				7,012				5,846				6,930	6,930	6,930	7,012	5,846
Singapore
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue													3,969			6,549	7,674
Long-lived assets	19,336				18,282				17,805				19,336	19,336	19,336	18,282	17,805
Indonesia
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue													3,206			9,706	7,482
Long-lived assets	139				117				98				139	139	139	117	98
Philippines
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue													2,140			5,991	6,483
Long-lived assets	661				729				448				661	661	661	729	448
United Arab Emirates
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue													3,335			683	1,042
Long-lived assets	54,789				54,887				54,249				54,789	54,789	54,789	54,887	54,249
New Zealand
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue													1,804			1,955	2,015
Long-lived assets	513				578				158				513	513	513	578	158
Mauritius
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue													0			0	3,140
Long-lived assets	$ 4,665				$ 4,643				$ 0				4,665	$ 4,665	$ 4,665	4,643	0
Primarily India
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue													$ 388,300			$ 320,000	$ 217,500