Net Income Per Share - Computation of Basic and Diluted Net Income Per Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Earnings Per Share [Abstract]
Net income attributable to stockholders of Sapient Corporation	$ 23,286	$ 22,793	$ 36,911	$ 28,708
Basic net income per share:
Weighted average common shares outstanding (in shares)	141,850	138,791	141,135	138,112
Basic net income per share attributable to stockholders of Sapient Corporation (in dollars per share)	$ 0.16	$ 0.16	$ 0.26	$ 0.21
Diluted net income per share:
Weighted average common shares outstanding (in shares)	141,850	138,791	141,135	138,112
Weighted average dilutive common share equivalents (in shares)	2,202	4,110	2,652	4,446
Weighted average common shares and dilutive common share equivalents (in shares)	144,052	142,901	143,787	142,558
Diluted net income per share attributable to stockholders of Sapient Corporation (in dollars per share)	$ 0.16	$ 0.16	$ 0.26	$ 0.20
Anti-dilutive options and share-based awards not included in the calculation (in shares)	1,774	28	10	14