CONSOLIDATED STATEMENTS OF CHANGES IN REDEEMABLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (USD $) In Thousands, except Share data	Series A-1 and A-2, Convertible Redeemable Preferred Stock USD ($)	Common Stock [Member] USD ($)	Common Stock [Member] Initial Public Offering USD ($)	Common Stock [Member] Instant Information Inc	Common Stock [Member] Thoughtcorp Inc	Common Stock [Member] Empathy Lab LLC	Series A-3 Convertible Preferred Stock [Member]	Additional Paid-in Capital USD ($)	Additional Paid-in Capital Initial Public Offering USD ($)	Additional Paid-in Capital Instant Information Inc USD ($)	Additional Paid-in Capital Thoughtcorp Inc USD ($)	Additional Paid-in Capital Empathy Lab LLC USD ($)	Retained Earnings USD ($)	Treasury Stock USD ($)	Treasury Stock Thoughtcorp Inc USD ($)	Treasury Stock Empathy Lab LLC USD ($)	Accumulated Other Comprehensive Income USD ($)	Total USD ($)	Initial Public Offering USD ($)	Instant Information Inc USD ($)	Thoughtcorp Inc USD ($)	Empathy Lab LLC USD ($)	Puttable Common Stock [Member] USD ($)
Beginning Balance at Dec. 31, 2010	$ 68,377	$ 17						$ 36,750					$ 47,718	$ (15,972)			$ (2,264)	$ 66,249					$ 332
Beginning Balance (in shares) at Dec. 31, 2010	2,439,739	17,054,408					290,277																56,896
Accretion of A-2 preferred stock to redemption value	17,563												(17,563)					(17,563)
Stock-based compensation expense								2,866										2,866
Proceeds from stock options exercises (in shares)		47,600																47,600
Proceeds from stock options exercises								72										72
Put option expiry (in shares)		56,896																56,896					(56,896)
Put option expiry								332										332					(332)
Currency translation adjustment																	(1,250)	(1,250)
Net income													44,353					44,353
Ending Balance at Dec. 31, 2011	85,940	17						40,020					74,508	(15,972)			(3,514)	95,059
Ending Balance (in shares) at Dec. 31, 2011	2,439,739	17,158,904					290,277
Stock issued (in shares)			2,900,000
Stock issued			3						32,361										32,364
Conversion to common stock (in shares)	(2,439,739)	21,840,128					(290,277)
Conversion to common stock	(85,940)	22						85,918										85,940
Offering issuance costs									(3,395)										(3,395)
Issuance of restricted stock		213,656
Stock issued in connection with acquisition (in shares)				53,336	434,546	326,344														53,336
Stock issued in connection with acquisition										640	(346)	(2,969)			3,953	2,969				640	3,607
Stock-based compensation expense								6,826										6,826
Proceeds from stock options exercises (in shares)		1,515,580																1,552,742
Proceeds from stock options exercises		2						4,963										4,965
Treasury stock retirement								(353)						353
Excess tax benefits								3,297										3,297
Currency translation adjustment																	2,493	2,493
Net income													54,484					54,484
Stock issued under the 2012 Non-Employee Directors Compensation Plan (Note 14)			2,900,000
Ending Balance at Dec. 31, 2012		44						166,962					128,992	(8,697)			(1,021)	286,280
Ending Balance (in shares) at Dec. 31, 2012		44,442,494
Stock issued (in shares)		14,041
Stock issued in connection with acquisition (in shares)						1,483
Stock issued in connection with acquisition																13						(13)
Stock-based compensation expense								13,150										13,150
Proceeds from stock options exercises (in shares)		2,156,898																2,156,898
Proceeds from stock options exercises		2						9,285										9,287
Excess tax benefits								6,201										6,201
Currency translation adjustment																	(811)	(811)
Net income													61,994					61,994
Stock issued under the 2012 Non-Employee Directors Compensation Plan (Note 14)		14,041
Ending Balance at Dec. 31, 2013		$ 46						$ 195,585					$ 190,986	$ (8,684)			$ (1,832)	$ 376,101
Ending Balance (in shares) at Dec. 31, 2013		46,614,916