Mack-Cali Realty Corporation Stockholders' Equity (Schedule Of Stock Option Plans) (Details) (USD $) In Thousands, except Share data	9 Months Ended
Sep. 30, 2011
Mack-Cali Realty Corporation Stockholders' Equity [Abstract]
Shares Under Options - Outstanding as January 1, 2011	295,676
Share Under Options - Exercised	(107,806)
Share Under Options - Cancelled	(4,000)
Shares Under Options - Outstanding at September 30, 2011	183,870
Shares Under Options - Options exercisable at September 30, 2011	183,870
Shares Under Options - Available for grant at September 30, 2011	2,425,073
Weighted Average Exercise Price - Outstanding as January 1, 2011	$ 29.05
Weighted Average Exercise Price - Exercised	$ 28.27
Weighted Average Exercise Price - Cancelled	$ 28.80
Weighted Average Exercise Price - Outstanding at September 30, 2011	$ 29.51
Aggregate Intrinsic Value, Outstanding as January 1, 2011	$ 1,186
Outstanding stock option price range, lower range	$ 28.47
Outstanding stock option price range, upper range	$ 45.47

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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The weighted average price at which option holders acquired shares when converting their stock options into shares under the plan during the reporting period.

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The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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The weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated during the reporting period due to noncompliance with plan terms during the reporting period.

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The total dollar difference between fair values of the underlying shares reserved for issuance and exercise prices pertaining to options outstanding under the plan as of the balance sheet date.

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Weighted average exercise price as of the balance sheet date for those equity-based payment arrangements exercisable and outstanding.

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