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Summary of Significant accounting policies (Tables) | 12 Months Ended
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Dec. 31, 2014
Summary of Significant Accounting Policies [Abstract] |
Reconciliation Of Net Income Attributable To Common Stockholders To Estimated Taxable Income [Table Text Block] |
| (Unaudited and in thousands) | Year Ended December 31, |  |
|  |  | 2014 |  | 2013 |  | 2012 |  |
| Net income attributable to Alexander’s | $ | 67,925 |  | $ | 56,915 |  | $ | 674,387 |  |
| Straight-line rent adjustments |  | (2,538) |  |  | (3,707) |  |  | (4,475) |  |
| Depreciation and amortization timing differences |  | 2,283 |  |  | 2,134 |  |  | 910 |  |
| Interest expense |  | 10 |  |  | 27 |  |  | 29 |  |
| Reversal of liability for income taxes |  | (420) |  |  | (206) |  |  | - |  |
| Additional tax gain on sale of the Kings Plaza |  |  |  |  |  |  |  |  |  |
|  | Regional Shopping Center |  | (357) |  |  | - |  |  | 23,928 |  |
| Other |  | 1,112 |  |  | (2,213) |  |  | 4,396 |  |
| Estimated taxable income | $ | 68,015 |  | $ | 52,950 |  | $ | 699,175 |  |

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- Definition Table reconciling net income attributable to common stockholders to estimated taxable income + References No definition available. + Details
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- Details
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