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COMMITMENTS AND CONTINGENCIES (Details) (USD $) | 1 Months Ended |  |  | 0 Months Ended
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May 31, 2011 class_action_lawsuits | Sep. 30, 2013 current_litigation_matters | Jun. 30, 2011 | Feb. 16, 2012 New Term Loan [Member] CoStar Group [Member] LoopNet [Member] | Feb. 16, 2012 New Revolving Credit Facility [Member] CoStar Group [Member] LoopNet [Member]
Business Acquisition [Line Items] |  |  |  |  |
Debt instrument borrowing capacity |  |  |  | $ 175,000,000 | $ 50,000,000
Term of loan (in years) |  |  |  | 5 years | 5 years
Class action lawsuits brought by alleged LoopNet stockholders (in lawsuits) | 3 |  |  |  |
Memorandum of understanding in which they agreed on the terms of a settlement of litigation |  |  | $ 200,000 |  |
Number of minimum of current litigation matters (in claims) |  | 1 |  |  |

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