Property and Equipment, net - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Owned Assets:
Owned assets, gross	$ 236,298	$ 228,850
Less: Accumulated depreciation and amortization	(163,600)	(155,798)
Owned assets, net	72,698	73,052
Right-of-use assets under finance leases:
Finance lease, right of use asset, gross	1,845	1,459
Less: Accumulated depreciation and amortization	(1,096)	(1,001)
Property and equipment, net	749	458
Property and equipment, net	73,447	73,510
Network equipment and computers
Owned Assets:
Owned assets, gross	88,566	85,921
Software
Owned Assets:
Owned assets, gross	71,419	69,752
Leasehold improvements
Owned Assets:
Owned assets, gross	40,312	39,533
Right-of-use assets under finance leases:
Finance lease, right of use asset, gross	794	778
Office furniture and equipment
Owned Assets:
Owned assets, gross	20,783	20,097
Right-of-use assets under finance leases:
Finance lease, right of use asset, gross	344	53
Motor vehicles
Owned Assets:
Owned assets, gross	719	635
Right-of-use assets under finance leases:
Finance lease, right of use asset, gross	$ 707	628
Buildings
Owned Assets:
Estimated useful lives	30 years
Owned assets, gross	$ 1,150	1,140
Land
Owned Assets:
Owned assets, gross	753	746
Capital work in progress
Owned Assets:
Owned assets, gross	$ 12,596	$ 11,026
Minimum | Network equipment and computers
Owned Assets:
Estimated useful lives	3 years
Minimum | Software
Owned Assets:
Estimated useful lives	3 years
Minimum | Leasehold improvements
Owned Assets:
Estimated useful lives	3 years
Minimum | Office furniture and equipment
Owned Assets:
Estimated useful lives	3 years
Minimum | Motor vehicles
Owned Assets:
Estimated useful lives	2 years
Maximum | Network equipment and computers
Owned Assets:
Estimated useful lives	5 years
Maximum | Software
Owned Assets:
Estimated useful lives	5 years
Maximum | Leasehold improvements
Owned Assets:
Estimated useful lives	8 years
Maximum | Office furniture and equipment
Owned Assets:
Estimated useful lives	8 years
Maximum | Motor vehicles
Owned Assets:
Estimated useful lives	5 years