Segment reporting (Tables)

3 Months Ended

12 Months Ended

Mar. 31, 2018

Dec. 31, 2017

Segment Reporting [Abstract]

Net Revenues for Service Type

	Three months ended March 31,
	2017	2018
Business process outsourcing	$            511,283	$             574,061
Information technology services	111,712	114,851
Total net revenues	$            622,995	$            688,912

Net revenues by service type are as follows:

	Year ended December 31,
	2015		2016		2017
Business process outsourcing	$	1,933,095	$	2,083,450	$	2,264,335
Information technology services		527,949		487,306		472,594
Total net revenues	$	2,461,044	$	2,570,756	$	2,736,929

Revenues from Clients Based on Industry Serviced

	Three months ended March 31,
	2017	2018
Banking, financial services and insurance	$           247,012	$            275,627
Manufacturing, including pharmaceuticals and medical equipment manufacturing	229,214	247,125
Technology, healthcare and other services	146,769	166,160
Total net revenues	$            622,995	$            688,912

Revenues from clients based on the industry serviced are as follows:

	Year ended December 31,
	2015		2016		2017
Banking, financial services and insurance	$	1,030,584	$	1,055,704	$	1,105,731
Manufacturing, including pharmaceuticals    and medical equipment manufacturing		878,570		958,779		1,002,973
Technology, healthcare and other services		551,890		556,273		628,225
Total net revenues	$	2,461,044	$	2,570,756	$	2,736,929

Net Revenues from Geographic Areas Based on Location of Service Delivery Centers

	Three months ended  March 31,
	2017	2018
India	$            411,055	$            389,134
Asia, other than India	66,662	79,461
North and Latin America	85,042	152,280
Europe	60,236	68,037
Total net revenues	$            622,995	$            688,912

Net revenues from geographic areas based on the location of the Company’s service delivery centers are as follows. A portion of net revenues attributable to India consists of net revenues for services performed by delivery centers in India or at clients’ premises outside of India by business units or personnel normally based in India.

	Year ended December 31,
	2015		2016		2017
India	$	1,687,699	$	1,804,113	$	1,712,783
Asia, other than India		238,529		249,839		286,338
North and Latin America		304,879		282,434		455,059
Europe		229,937		234,370		282,749
Total net revenues	$	2,461,044	$	2,570,756	$	2,736,929

Property, Plant and Equipment, Net by Geographic Areas

26. Segment reporting (Continued)

Property, plant and equipment, net by geographic region are as follows:

	As of December 31,
	2016		2017
India	$	116,417	$	125,490
Asia, other than India		13,549		15,899
North and Latin America		44,633		38,438
Europe		18,619		27,203
Total	$	193,218	$	207,030