Segment Information - Service Revenues and Income Before Income Taxes Attributable to Operating Segments (Parenthetical) (Detail) (USD $)	3 Months Ended				6 Months Ended
	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013
Segment Reporting Information [Line Items]
Stock-based compensation expense					$ 16,094,000		$ 14,990,000
Restructuring and other related charges (benefits)			(31,000)				1,983,000
Amortization of purchased intangible assets	3,822,000		3,263,000		7,041,000		6,920,000
Acquisition costs and other related charges (benefits)	46,000		(1,284,000)		428,000		(384,000)
Impairment of intangible asset	0		0		0		1,494,000
Total reconciling items	(36,676,000)		(34,724,000)		(58,170,000)		(46,818,000)
SapientNitro [Member]
Segment Reporting Information [Line Items]
Restructuring and other related charges (benefits)							1,300,000
Sapient Global Markets [Member]
Segment Reporting Information [Line Items]
Restructuring and other related charges (benefits)							500,000
Reconciling Items [Member]
Segment Reporting Information [Line Items]
Centrally managed functions	65,406,000		58,043,000		130,750,000		115,227,000
Stock-based compensation expense	8,127,000		7,834,000		16,094,000		14,990,000
Restructuring and other related charges (benefits)	1,871,000		(31,000)		1,864,000		1,983,000
Amortization of purchased intangible assets	3,822,000		3,263,000		7,041,000		6,920,000
Acquisition costs and other related charges (benefits)	46,000		(1,284,000)		428,000		(384,000)
Impairment of intangible asset	0		0		0		1,494,000
Other	0	[1]	0	[1]	2,815,000	[1]	0	[1]
Interest and other income, net	(1,334,000)		(1,200,000)		(2,992,000)		(2,072,000)
Total reconciling items	$ 77,938,000	[2]	$ 66,625,000	[2]	$ 156,000,000	[2]	$ 138,158,000	[2]

[1] In the six months ended June 30, 2014, the Company incurred a $2.8 million one-time project personnel expense charge to reimburse employees for costs incurred as part of a restructuring of a global travel program. As this is unrelated to current operations, and neither comparable to prior periods nor predictive of future results, the Company has excluded it from the reportable segments operating income in evaluating management performance.

[2] Adjustments that are made to reconcile total reportable segments operating income to consolidated income before income taxes include the following (in thousands): Three Months Ended June 30,Six Months Ended June 30, 2014201320142013 As RestatedAs RestatedCentrally managed functions$65,406$58,043$130,750$115,227Stock-based compensation expense8,1277,83416,09414,990Restructuring and other related charges (benefits)1,871(31)1,8641,983Amortization of purchased intangible assets3,8223,2637,0416,920Acquisition costs and other related charges (benefits)46(1,284)428(384)Impairment of intangible asset———1,494Other (3)——2,815—Interest and other income, net(1,334)(1,200)(2,992)(2,072)Total reconciling items$77,938 $66,625 $156,000$138,158