SUBSEQUENT EVENTS (Details) (USD $)	3 Months Ended		6 Months Ended			1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended			1 Months Ended		1 Months Ended	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010	Jul. 31, 2011 MediaMind Technologies, Inc. ("MediaMind")	Sep. 30, 2011 MediaMind Technologies, Inc. ("MediaMind")	Jun. 30, 2011 MediaMind Technologies, Inc. ("MediaMind")	Jun. 30, 2011 MediaMind Technologies, Inc. ("MediaMind")	Jun. 30, 2010 MediaMind Technologies, Inc. ("MediaMind")	Dec. 31, 2010 MediaMind Technologies, Inc. ("MediaMind")	Jul. 26, 2011 MediaMind Technologies, Inc. ("MediaMind")	Mar. 31, 2011 MediaMind Technologies, Inc. ("MediaMind")	Jul. 31, 2011 MediaMind Technologies, Inc. ("MediaMind") Amended Credit Facility	Jun. 30, 2011 Revolving Credit Facility	Jul. 31, 2011 Term Loans	Jun. 30, 2011 Term Loans	Jul. 26, 2011 Term Loans	Jul. 26, 2011 Revolving Loans
Subsequent events
Cash paid to acquire issued and outstanding shares												$ 498,000,000
Cash paid to the holders of vested stock options that were "in-the-money"												70,000,000
Acquisition related costs incurred						13,000,000
Acquisition related costs to be expensed							10,000,000	3,000,000
Percentage of revenue generated from outside the United States (as a percent)											72.00%
Revenues	67,852,000	58,190,000	131,362,000	110,521,000					44,700,000	37,200,000	80,846,000
Cost of revenues	22,935,000	16,998,000	44,449,000	33,710,000							4,289,000
Operating expenses	26,403,000	21,642,000	46,978,000	41,713,000							63,339,000
Operating income	18,514,000	19,550,000	39,935,000	35,098,000							13,218,000
Other income											577,000
Income before income taxes	18,345,000	15,103,000	39,825,000	28,575,000							13,795,000
Provision for income taxes	7,847,000	6,273,000	16,439,000	11,867,000							3,843,000
Net income	10,213,000	9,000,000	22,892,000	17,042,000							9,952,000
Total current assets	127,225,000		127,225,000		144,748,000								132,117,000
Total assets	534,405,000		534,405,000		520,004,000								147,042,000
Total current liabilities	23,574,000		23,574,000		19,135,000								10,847,000
Long-term liabilities													4,768,000
Stockholders' equity	506,836,000		506,836,000		496,912,000								131,427,000
Total liabilities and stockholders' equity	534,405,000		534,405,000		520,004,000								147,042,000
Pro forma revenues had MediaMind, MIJO and Match Point been acquired on January 1, 2010			181,200,000	165,400,000
Credit facility
Amount borrowed to finance business acquisition														490,000,000
Maximum borrowing capacity															150,000,000	490,000,000			120,000,000
Interest rate basis - option 1																LIBOR
Interest rate margin - option 1 (as a percent)																		4.50%
Interest rate on debt - option 2 (as a percent)																		5.75%
Quarterly principal payments of debt - option 2																1,225,000
Yearly principal payments of debt - option 2																	$ 4,900,000
Percentage of excess cash flow required to be paid as mandatory prepayment provisions under the Term Loans (as a percent)																	50.00%