Fair Value Measurements and the Fair Value Option - Schedule of Significant Inputs (Details)	9 Months Ended
Sep. 30, 2015
Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Entity credit risk percentage	1.00%
Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Entity credit risk percentage	4.87%
Office [Member] \| Minimum [Member] \| Income and Market Approach Technique [Member] \| Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Capitalization Rates	5.25%
Discount Rates	7.00%
Office [Member] \| Maximum [Member] \| Income and Market Approach Technique [Member] \| Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Capitalization Rates	8.25%
Discount Rates	11.00%
Retail [Member] \| Minimum [Member] \| Income and Market Approach Technique [Member] \| Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Capitalization Rates	6.70%
Discount Rates	8.00%
Retail [Member] \| Maximum [Member] \| Income and Market Approach Technique [Member] \| Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Capitalization Rates	7.00%
Discount Rates	9.00%
Hotel [Member] \| Income and Market Approach Technique [Member] \| Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Capitalization Rates	6.50%
Discount Rates	7.50%
Multifamily [Member] \| Minimum [Member] \| Income and Market Approach Technique [Member] \| Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Capitalization Rates	4.40%
Discount Rates	4.90%
Multifamily [Member] \| Maximum [Member] \| Income and Market Approach Technique [Member] \| Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Capitalization Rates	7.00%
Discount Rates	10.75%
Loan [Member] \| Minimum [Member] \| Income and Market Approach Technique [Member] \| Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount Rates	12.00%
Loan [Member] \| Maximum [Member] \| Income and Market Approach Technique [Member] \| Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount Rates	25.50%
Land and condominium units [Member] \| Minimum [Member] \| Income and Market Approach Technique [Member] \| Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount Rates	8.00%
Land and condominium units [Member] \| Maximum [Member] \| Income and Market Approach Technique [Member] \| Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount Rates	9.00%

Fair Value Inputs, Capitalization Rate

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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- Definition

Interest rate used to find the present value of an amount to be paid or received in the future as an input to measure fair value. For example, but not limited to, weighted average cost of capital (WACC), cost of capital, cost of equity and cost of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (bbb)

-URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258

+ Details

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- Definition

Risk associated with risk of default, credit spread risk and downgrade risk, expressed as a percentage, used as an input to measure fair value.

+ References

+ Details

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- Details

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