Quarterly report pursuant to Section 13 or 15(d)

Disclosure Of Fair Value Of Assets And Liabilities (Schedule Of Valuation Techniques And Significant Unobservable Assumptions) (Details)

v3.21.2
Disclosure Of Fair Value Of Assets And Liabilities (Schedule Of Valuation Techniques And Significant Unobservable Assumptions) (Details)
Sep. 30, 2021
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Office Properties Held For Sale [Member] | Suburban [Member] | Valuation Technique, Discounted Cash Flow [Member] | Measurement Assumptions, Discount Rates [Member]  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]  
Servicing Asset, Measurement Input 0.10
Office Properties Held For Sale [Member] | Suburban [Member] | Valuation Technique, Discounted Cash Flow [Member] | Measurement Assumptions, Market Rental Rates Per Square Foot [Member]  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]  
Servicing Asset, Measurement Input 34.50
Office Properties Held For Sale [Member] | Suburban [Member] | Valuation Technique, Discounted Cash Flow [Member] | Minimum [Member] | Measurement Assumptions, Exit Capitalization Rates [Member]  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]  
Servicing Asset, Measurement Input 0.085
Office Properties Held For Sale [Member] | Suburban [Member] | Valuation Technique, Discounted Cash Flow [Member] | Maximum [Member] | Measurement Assumptions, Exit Capitalization Rates [Member]  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]  
Servicing Asset, Measurement Input 0.0925
Office Properties Held For Sale [Member] | Waterfront [Member] | Valuation Technique, Discounted Cash Flow [Member] | Measurement Assumptions, Discount Rates [Member]  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]  
Servicing Asset, Measurement Input 0.08
Office Properties Held For Sale [Member] | Waterfront [Member] | Valuation Technique, Discounted Cash Flow [Member] | Minimum [Member] | Measurement Assumptions, Market Rates Per Square Foot [Member]  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]  
Servicing Asset, Measurement Input 48.00
Office Properties Held For Sale [Member] | Waterfront [Member] | Valuation Technique, Discounted Cash Flow [Member] | Maximum [Member] | Measurement Assumptions, Market Rates Per Square Foot [Member]  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]  
Servicing Asset, Measurement Input 51.00
Land Holdings Held For Sale [Member] | Suburban [Member] | Valuation Technique, Consensus Pricing Model [Member] | Measurement Assumptions, Market Rates Per Square Foot [Member]  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]  
Servicing Asset, Measurement Input 12.00
Land Holdings Held For Sale [Member] | Suburban [Member] | Valuation Technique, Consensus Pricing Model [Member] | Minimum [Member] | Measurement Assumptions, Market Rates Per Square Foot [Member]  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]  
Servicing Asset, Measurement Input 43,000
Land Holdings Held For Sale [Member] | Suburban [Member] | Valuation Technique, Consensus Pricing Model [Member] | Maximum [Member] | Measurement Assumptions, Market Rates Per Square Foot [Member]  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]  
Servicing Asset, Measurement Input 54,000
Land Holdings Held For Sale [Member] | Waterfront [Member] | Valuation Technique, Consensus Pricing Model [Member] | Minimum [Member] | Measurement Assumptions, Market Rates Per Square Foot [Member]  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]  
Servicing Asset, Measurement Input 60,000
Land Holdings Held For Sale [Member] | Waterfront [Member] | Valuation Technique, Consensus Pricing Model [Member] | Maximum [Member] | Measurement Assumptions, Market Rates Per Square Foot [Member]  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]  
Servicing Asset, Measurement Input 85,000