Acquisitions (Details) (USD $)	3 Months Ended								12 Months Ended			36 Months Ended	12 Months Ended										0 Months Ended	12 Months Ended	0 Months Ended			1 Months Ended	12 Months Ended	1 Months Ended				12 Months Ended			0 Months Ended				0 Months Ended		12 Months Ended				0 Months Ended				12 Months Ended			0 Months Ended				0 Months Ended		1 Months Ended	3 Months Ended	12 Months Ended				1 Months Ended	0 Months Ended			1 Months Ended	3 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 item	Dec. 31, 2012 Minimum	Dec. 31, 2012 Maximum	Dec. 31, 2012 Customer relationships	Dec. 31, 2011 Customer relationships	Dec. 31, 2012 Trade name	Dec. 31, 2011 Trade name	Dec. 31, 2012 Developed technology	Dec. 31, 2011 Developed technology	Dec. 31, 2012 Noncompetition agreements	Dec. 31, 2011 Noncompetition agreements	Jul. 31, 2012 North Country, Inc. item	Dec. 31, 2012 North Country, Inc.	Jul. 31, 2012 North Country, Inc. Customer relationships	Jul. 31, 2012 North Country, Inc. Trade name	Jul. 31, 2012 North Country, Inc. Noncompetition agreements	Apr. 30, 2012 Peer39, Inc	Dec. 31, 2012 Peer39, Inc	Apr. 30, 2012 Peer39, Inc Customer relationships	Apr. 30, 2012 Peer39, Inc Trade name	Apr. 30, 2012 Peer39, Inc Developed technology	Apr. 30, 2012 Peer39, Inc Noncompetition agreements	Dec. 31, 2012 EyeWonder LLC and Chors GmbH ("EyeWonder")	Dec. 31, 2011 EyeWonder LLC and Chors GmbH ("EyeWonder")	Sep. 01, 2011 EyeWonder LLC and Chors GmbH ("EyeWonder")	Sep. 01, 2011 EyeWonder LLC and Chors GmbH ("EyeWonder") Customer relationships	Sep. 01, 2011 EyeWonder LLC and Chors GmbH ("EyeWonder") Trade name	Sep. 01, 2011 EyeWonder LLC and Chors GmbH ("EyeWonder") Developed technology	Sep. 01, 2011 EyeWonder LLC and Chors GmbH ("EyeWonder") Noncompetition agreements	Sep. 01, 2011 EyeWonder LLC and Chors GmbH ("EyeWonder") Noncompetition agreements Minimum	Sep. 01, 2011 EyeWonder LLC and Chors GmbH ("EyeWonder") Noncompetition agreements Maximum	Dec. 31, 2011 MediaMind Technologies ("Mediamind")	Dec. 31, 2012 MediaMind Technologies ("Mediamind")	Jul. 26, 2011 MediaMind Technologies ("Mediamind")	Jul. 26, 2011 MediaMind Technologies ("Mediamind") Term Loans	Jul. 26, 2011 MediaMind Technologies ("Mediamind") Customer relationships	Jul. 26, 2011 MediaMind Technologies ("Mediamind") Trade name	Jul. 26, 2011 MediaMind Technologies ("Mediamind") Developed technology	Jul. 26, 2011 MediaMind Technologies ("Mediamind") Noncompetition agreements	Dec. 31, 2011 MIJO Corporation ("MIJO")	Dec. 31, 2012 MIJO Corporation ("MIJO")	Apr. 02, 2011 MIJO Corporation ("MIJO")	Apr. 02, 2011 MIJO Corporation ("MIJO") Customer relationships	Apr. 02, 2011 MIJO Corporation ("MIJO") Trade name	Apr. 02, 2011 MIJO Corporation ("MIJO") Developed technology	Apr. 02, 2011 MIJO Corporation ("MIJO") Noncompetition agreements	Apr. 02, 2011 MIJO Corporation ("MIJO") Noncompetition agreements Minimum	Apr. 02, 2011 MIJO Corporation ("MIJO") Noncompetition agreements Maximum	Oct. 31, 2010 Match Point item	Dec. 31, 2011 Match Point	Dec. 31, 2012 Match Point	Dec. 31, 2011 Match Point	Dec. 31, 2010 Match Point	Oct. 02, 2010 Match Point	Oct. 31, 2010 Match Point Maximum	Oct. 02, 2010 Match Point Customer relationships	Oct. 02, 2010 Match Point Trade name	Oct. 02, 2010 Match Point Noncompetition agreements	Apr. 30, 2012 Chors Unit	Mar. 31, 2012 Chors Unit	Apr. 02, 2012 Chors Unit	Apr. 02, 2011 Chors Unit Maximum
Acquisition
Number of businesses acquired												6
Net assets acquired																							$ 3,700,000					$ 15,700,000								$ 61,000,000									$ 499,300,000								$ 43,800,000												$ 27,700,000
Transfer Majority of Chors Unit
Consideration received for transfer of assets																																																																						100,000
Revenue commitment																																																																								5,000,000
Number of years for incremental revenue from closing																																																																						1 year
Revenue from transferred assets and employees																																																																							1,300,000
Income before income taxes																																																																							300,000
Maximum penalty amount in the event of shortfall of revenue commitment																																																																									2,000,000
Acquisition
Total consideration paid																												15,700,000
Total consideration paid in cash for acquired entity																							1,800,000					10,100,000								61,000,000									499,300,000								43,800,000												26,700,000
Amount held back from purchase price for certain transaction costs																																				5,000,000
Transaction cost																																		5,000,000	1,900,000								11,700,000								300,000													300,000
Receivables attributable to acquired balances																																		2,800,000
Contingent consideration	427,000				738,000				427,000	738,000		427,000											1,900,000																																										2,600,000
Contingent consideration, low end of range																							0
Contingent consideration, high end of range																							1,900,000
Number of future revenue targets for contingent payments																							3																																					3
Contingent payments for each measurement criteria																																																																		1,000,000
Payments resulting from meeting of 2010 adjusted earnings criterion																																																															1,000,000
Reversal of payments resulting from not meeting 2011 adjusted earnings criterion																																																													900,000
Expected payment resulting from meeting of 2012 adjusted earnings criterion																																																														1,000,000
Acquired intangible assets																									1,100,000	200,000	500,000
Total consideration paid for acquired entity (in shares)																												357,143
Total installment payment for acquired entity	2,331,000								2,331,000			2,331,000																2,300,000																																					3,000,000
Period from acquisition date in which installment payment will be made																												1 year
Acquired intangible assets, weighted average term																									10 years	6 years	5 years			10 years	10 years	6 years	4 years				12 years	5 years	3 years		3 years	5 years					11 years	10 years	4 years	5 years				15 years	10 years	6 years		3 years	5 years								10 years	6 years	5 years
Weighted average amortization period of intangible assets									10 years 3 months 18 days	10 years 3 months 18 days			3 years	15 years	11 years 1 month 6 days	11 years 2 months 12 days	12 years 2 months 12 days	12 years 2 months 12 days	4 years 4 months 24 days	4 years 3 months 18 days	4 years 8 months 12 days	4 years 9 months 18 days	8 years 2 months 12 days					7 years 1 month 6 days
Gross receivables																							400,000					800,000						10,100,000										32,700,000								4,700,000										3,000,000
Estimated fair value of gross receivables																							400,000					800,000						10,100,000										32,300,000								4,700,000										2,400,000
Revenue recognized																								1,400,000					4,400,000						12,400,000								45,200,000								16,200,000													4,900,000
Income (loss) before income tax recognized																								300,000					1,400,000						(900,000)								(2,500,000)								2,500,000													700,000
Cash paid to holders of vested stock options																																													71,400,000
Maximum borrowing capacity																																														490,000,000
Purchase price allocation
Current assets																							500,000					2,400,000								13,400,000									139,000,000								5,100,000												2,800,000
Property and equipment																							700,000					700,000								2,300,000									9,100,000								4,000,000												800,000
Other assets																												500,000								1,600,000									12,700,000
Amortizable intangible assets																									1,100,000	200,000	500,000			3,100,000	200,000	1,800,000	1,000,000				10,700,000	1,800,000	1,300,000	2,200,000							62,400,000	10,000,000	14,300,000	7,600,000				7,800,000	1,800,000	2,600,000	4,600,000										8,700,000	1,700,000	3,800,000
Goodwill																							800,000					7,200,000								43,400,000									292,100,000								19,500,000												11,500,000
Total assets acquired																							3,800,000					16,900,000								76,700,000									547,200,000								45,400,000												29,300,000
Less deferred tax liabilities																																				(2,300,000)									(19,300,000)
Less other liabilities assumed																							(100,000)					(1,200,000)								(13,400,000)									(28,600,000)								(1,600,000)												(1,600,000)
Net assets acquired																							3,700,000					15,700,000								61,000,000									499,300,000								43,800,000												27,700,000
As Reported Information
Revenues	103,610,000	93,818,000	96,336,000	92,849,000	108,301,000	84,594,000	67,852,000	63,510,000	386,613,000	324,257,000	241,328,000
Income (loss) from continuing operations	(20,825,000)	(219,727,000)	518,000	1,279,000	5,848,000	(2,697,000)	10,498,000	12,888,000	(238,755,000)	26,537,000	45,302,000
Income (loss) per share - continuing operations: Basic (in dollars per share)	$ (0.75)	$ (7.96)	$ 0.02	$ 0.05	$ 0.21	$ (0.10)	$ 0.38	$ 0.46	$ (8.69)	$ 0.96	$ 1.65
Income (loss) per share - continuing operations: Diluted (in dollars per share)	$ (0.75)	$ (7.96)	$ 0.02	$ 0.05	$ 0.21	$ (0.10)	$ 0.38	$ 0.46	$ (8.69)	$ 0.95	$ 1.63
Pro Forma Information
Revenue									388,655,000	406,224,000
Income (loss) from continuing operations									$ 240,114,000	$ 6,417,000
Income (loss) per share - continuing operations: Basic (in dollars per share)									$ (8.70)	$ 0.23
Income (loss) per share - continuing operations: Diluted (in dollars per share)									$ (8.70)	$ 0.23