Geographic Information (Details) $ in Thousands	3 Months Ended												12 Months Ended
	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, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2019 USD ($) ProductService_Groups	Dec. 31, 2019 USD ($)	Dec. 31, 2019 USD ($) segment	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Revenues from External Customers and Long-Lived Assets [Line Items]
Number of reportable segments | segment															1
Operating revenue	$ 146,183	$ 147,233	$ 144,275	$ 142,924	$ 136,327	$ 128,643	$ 124,626	$ 108,230	$ 104,681	$ 92,800	$ 87,387	$ 79,103		$ 580,615		$ 497,826	$ 363,971
Long-lived assets	1,227,685				1,183,567				860,081				$ 1,227,685	1,227,685	$ 1,227,685	1,183,567	860,081
Number of operating segments													3		1
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue														182,530		196,984	211,895
Long-lived assets	395,225				390,551				394,112				$ 395,225	395,225	$ 395,225	390,551	394,112
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue														4,805		5,611	7,522
Long-lived assets	7,012				5,846				6,601				7,012	7,012	7,012	5,846	6,601
Latin America
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue														19,755		19,866	21,128
Long-lived assets	17,176				16,348				22,300				17,176	17,176	17,176	16,348	22,300
Singapore
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue														6,549		7,674	6,330
Long-lived assets	18,282				17,805				17,475				18,282	18,282	18,282	17,805	17,475
New Zealand
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue														1,955		2,015	1,933
Long-lived assets	578				158				247				578	578	578	158	247
Primarily India
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue														300,678		196,372	61,857
Long-lived assets	700,986				672,699				338,130				700,986	700,986	700,986	672,699	338,130
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue														14,695		15,387	17,062
Long-lived assets	24,508				23,880				25,687				24,508	24,508	24,508	23,880	25,687
AUSTRALIA
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue														33,268		35,770	34,366
Long-lived assets	3,541				1,485				1,174				3,541	3,541	3,541	1,485	1,174
INDONESIA
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue														9,706		7,482	1,055
Long-lived assets	117				98				110				117	117	117	98	110
PHILIPPINES
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue														5,991		6,483	623
Long-lived assets	729				448				616				729	729	729	448	616
UNITED ARAB EMIRATES
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue														683		1,042	200
Long-lived assets	59,531				54,249				53,629				59,531	59,531	59,531	54,249	53,629
MAURITIUS
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue														0		3,140	0
Long-lived assets	$ 0				0				$ 0				$ 0	0	$ 0	0	0
India
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenue					$ 65,900									$ 320,000		$ 217,500	$ 64,300