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Stock Option and Incentive Plan Stock Option and Incentive Plan and Stock Purchase Plan (Tables) | 12 Months Ended
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Dec. 31, 2017
Stock Option and Incentive Plan and Stock Purchase Plan [Abstract] |
Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block] | A summary of the status of Boston Properties, Inc.’s stock options as of December 31, 2017, 2016 and 2015 and changes during the years then ended are presented below:
|  | Shares |  | Weighted-Average Exercise Price
Outstanding at December 31, 2014 |  | 553,312 |  |  | $ | 97.21 |
Exercised |  | (11,447 | ) |  | $ | 92.50 |
Special dividend adjustment |  | 5,264 |  |  | $ | 96.38 |
Outstanding at December 31, 2015 |  | 547,129 |  |  | $ | 96.38 |
Exercised |  | — |  |  | $ | — |
Outstanding at December 31, 2016 |  | 547,129 |  |  | $ | 96.38 |
Exercised |  | (6,688 | ) |  | $ | 99.15 |
Outstanding at December 31, 2017 |  | 540,441 |  |  | $ | 96.35 |
Schedule of Stock Options Outstanding [Table Text Block] | The following table summarizes information about Boston Properties, Inc.’s stock options outstanding at December 31, 2017:
Options Outstanding |  | Options Exercisable
Number Outstanding at 12/31/17 |  | Weighted-Average Remaining Contractual Life |  | Exercise Price |  | Number Exercisable at 12/31/17 |  | Exercise Price
118,502 |  |  | 3.1 years |  | $ | 86.86 |  |  | 118,502 |  |  | $ | 86.86 |
54,282 |  |  | 5.3 years |  | $ | 95.69 |  |  | 54,282 |  |  | $ | 95.69 |
202,030 |  |  | 5.1 years |  | $ | 98.46 |  |  | 202,030 |  |  | $ | 98.46 |
165,627 |  |  | 4.1 years |  | $ | 100.77 |  |  | 165,627 |  |  | $ | 100.77 |

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- Definition Tabular disclosure of the number and weighted-average exercise prices (or conversion ratios) for share options (or share units) that were outstanding at the beginning and end of the year, vested and expected to vest, exercisable or convertible at the end of the year, and the number of share options or share units that were granted, exercised or converted, forfeited, and expired during the year. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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