Subsequent Events	12 Months Ended
Dec. 31, 2016
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	SUBSEQUENT EVENTS On January 5, 2017, Gartner and CEB Inc. (NYSE: CEB) ("CEB"), an industry leader in providing best practice and talent management insights, announced that they had entered into a definitive agreement whereby Gartner will acquire all of the outstanding shares of CEB in a cash and stock transaction valued at approximately $2.6 billion. Gartner will also assume (and refinance) approximately $0.9 billion in CEB debt. The transaction has been unanimously approved by the Boards of Directors of both companies. Closing of the transaction is subject to the approval of CEB shareholders and the satisfaction of customary closing conditions, including applicable regulatory approvals. On February 1, 2017, the Federal Trade Commission granted early termination of the waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, applicable to the proposed transaction. Closing of the transaction is expected to be completed in the first half of 2017. In connection with the proposed acquisition, the Company entered into a commitment letter for the purposes of financing the majority of the cash consideration payable and to refinance CEB’s indebtedness. The commitment letter provides for a total of $2.275 billion in additional financing, which includes a seven-year senior secured term loan B facility of up to $1.375 billion, a 364-day senior unsecured bridge facility of up to $300.0 million, and a senior unsecured high-yield bridge facility of up to $600.0 million. It is expected that on or prior to the closing of the CEB acquisition, senior unsecured notes will be issued and sold to pursuant to an offering pursuant to Rule 144A or a private placement in lieu of a portion of, or all of the drawings under, the high-yield bridge facility. The Company expects that the proceeds from the additional financing described above, together with its balance sheet cash and available borrowing capacity under its revolving credit facility, will be sufficient to pay the aggregate cash consideration and refinance CEB's indebtedness, as well as pay for certain fees and expenses incurred in connection with the acquisition. On February 6, 2017, the Company filed a Registration Statement on Form S-4 with the SEC pertaining to the shares of Gartner common stock that will be issued in connection with the proposed transaction and a prospectus relating to the special meeting of the CEB stockholders that will be called for purposes of voting on the proposed transaction.

SUBSEQUENT EVENTS

On January 5, 2017, Gartner and CEB Inc. (NYSE: CEB) ("CEB"), an industry leader in providing best practice and talent management insights, announced that they had entered into a definitive agreement whereby Gartner will acquire all of the outstanding shares of CEB in a cash and stock transaction valued at approximately $2.6 billion. Gartner will also assume (and refinance) approximately $0.9 billion in CEB debt. The transaction has been unanimously approved by the Boards of Directors of both companies. Closing of the transaction is subject to the approval of CEB shareholders and the satisfaction of customary closing conditions, including applicable regulatory approvals. On February 1, 2017, the Federal Trade Commission granted early termination of the waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, applicable to the proposed transaction. Closing of the transaction is expected to be completed in the first half of 2017.

In connection with the proposed acquisition, the Company entered into a commitment letter for the purposes of financing the majority of the cash consideration payable and to refinance CEB’s indebtedness. The commitment letter provides for a total of $2.275 billion in additional financing, which includes a seven-year senior secured term loan B facility of up to $1.375 billion, a 364-day senior unsecured bridge facility of up to $300.0 million, and a senior unsecured high-yield bridge facility of up to $600.0 million. It is expected that on or prior to the closing of the CEB acquisition, senior unsecured notes will be issued and sold to pursuant to an offering pursuant to Rule 144A or a private placement in lieu of a portion of, or all of the drawings under, the high-yield bridge facility. The Company expects that the proceeds from the additional financing described above, together with its balance sheet cash and available borrowing capacity under its revolving credit facility, will be sufficient to pay the aggregate cash consideration and refinance CEB's indebtedness, as well as pay for certain fees and expenses incurred in connection with the acquisition.

On February 6, 2017, the Company filed a Registration Statement on Form S-4 with the SEC pertaining to the shares of Gartner common stock that will be issued in connection with the proposed transaction and a prospectus relating to the special meeting of the CEB stockholders that will be called for purposes of voting on the proposed transaction.