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Real Estate and Accumulated Depreciation - Estimated Useful Lives of Assets (Detail) | 12 Months Ended
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Dec. 31, 2020
Base building | Minimum |
Property Plant and Equipment Estimated Useful Lives [Line Items] |
Estimated useful life | 35 years
Base building | Maximum |
Property Plant and Equipment Estimated Useful Lives [Line Items] |
Estimated useful life | 50 years
Building components | Maximum |
Property Plant and Equipment Estimated Useful Lives [Line Items] |
Estimated useful life | 20 years

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- Definition Property Plant and Equipment Estimated Useful Lives [Line Items] + References No definition available. + Details
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Namespace Prefix: | bfs_
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- Definition Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment. + References No definition available. + Details
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- Details
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- Details
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Period Type: |

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- Details
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- Details
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Namespace Prefix: |
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Balance Type: |
Period Type: |