Mack-Cali Realty Corporation Stockholders' Equity (Earnings Per Share Tables - Diluted Computation of EPS) (Details) (USD $) In Thousands, except Per Share data	3 Months Ended	9 Months Ended
Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Mack-Cali Realty Corporation Stockholders' Equity [Abstract]
Income from continuing operations available to common shareholders	$ 20,500	$ 13,039	$ 53,562	$ 42,252
Add: Noncontrolling interest in operating partnership	3,015	2,150	8,031	7,047
Income from continuing operations for diluted earnings per share	23,515	15,189	61,593	49,299
Income (loss) from discontinued operations for diluted earnings per share				4,689
Net income available to common shareholders	$ 23,515	$ 15,189	$ 61,593	$ 53,988
Weighted average common shares	99,917	92,464	98,631	92,467
Income from continuing operations available to common shareholders	$ 0.24	$ 0.16	$ 0.62	$ 0.53
Income (loss) from discontinued operations available to common shareholders				$ 0.05
Net income available to common shareholders	$ 0.24	$ 0.16	$ 0.62	$ 0.58

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