Assets and Liabilities Measured at Fair Value on a Recurring Basis - Schedule of unobservable inputs related to Level 3 fair value measurements (Details) | 12 Months Ended |
Dec. 31, 2016 |
Minimum | Real Estate Properties and Joint Ventures | Discount Rate | Income Approach Valuation Technique | Office | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Discount Rate | 5.50% |
Terminal Capitalization Rate | 4.30% |
Minimum | Real Estate Properties and Joint Ventures | Discount Rate | Income Approach Valuation Technique | Industrial | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Discount Rate | 5.70% |
Terminal Capitalization Rate | 4.80% |
Minimum | Real Estate Properties and Joint Ventures | Discount Rate | Income Approach Valuation Technique | Residential | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Discount Rate | 5.30% |
Terminal Capitalization Rate | 3.80% |
Minimum | Real Estate Properties and Joint Ventures | Discount Rate | Income Approach Valuation Technique | Retail | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Discount Rate | 5.00% |
Terminal Capitalization Rate | 4.30% |
Minimum | Real Estate Properties and Joint Ventures | Direct Capitalization, Overall Capitalization Rate | Income Approach Valuation Technique | Office | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Overall Capitalization Rate | 3.80% |
Minimum | Real Estate Properties and Joint Ventures | Direct Capitalization, Overall Capitalization Rate | Income Approach Valuation Technique | Industrial | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Overall Capitalization Rate | 4.00% |
Minimum | Real Estate Properties and Joint Ventures | Direct Capitalization, Overall Capitalization Rate | Income Approach Valuation Technique | Residential | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Overall Capitalization Rate | 3.30% |
Minimum | Real Estate Properties and Joint Ventures | Direct Capitalization, Overall Capitalization Rate | Income Approach Valuation Technique | Retail | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Overall Capitalization Rate | 3.90% |
Minimum | Mortgage Loans Payable | Discount Rate | Residential | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Loan-to-Value Ratio | 29.50% |
Equivalency Rate | 2.90% |
Minimum | Mortgage Loans Payable | Discount Rate | Retail | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Loan-to-Value Ratio | 18.30% |
Equivalency Rate | 2.90% |
Minimum | Mortgage Loans Payable | Discount Rate | Office and Industrial | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Loan-to-Value Ratio | 35.70% |
Equivalency Rate | 3.70% |
Minimum | Mortgage Loans Payable | Net Present Value | Residential | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Loan-to-Value Ratio | 29.50% |
Weighted Average Cost of Capital Risk Premium Multiple | 1.20% |
Minimum | Mortgage Loans Payable | Net Present Value | Retail | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Loan-to-Value Ratio | 18.30% |
Weighted Average Cost of Capital Risk Premium Multiple | 1.10% |
Minimum | Mortgage Loans Payable | Net Present Value | Office and Industrial | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Loan-to-Value Ratio | 35.70% |
Weighted Average Cost of Capital Risk Premium Multiple | 1.20% |
Minimum | Loans Receivable | Discount Rate | Office, Retail and Storage | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Loan-to-Value Ratio | 55.60% |
Equivalency Rate | 4.20% |
Maximum | Real Estate Properties and Joint Ventures | Discount Rate | Income Approach Valuation Technique | Office | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Discount Rate | 8.30% |
Terminal Capitalization Rate | 7.30% |
Maximum | Real Estate Properties and Joint Ventures | Discount Rate | Income Approach Valuation Technique | Industrial | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Discount Rate | 8.70% |
Terminal Capitalization Rate | 8.00% |
Maximum | Real Estate Properties and Joint Ventures | Discount Rate | Income Approach Valuation Technique | Residential | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Discount Rate | 7.30% |
Terminal Capitalization Rate | 6.00% |
Maximum | Real Estate Properties and Joint Ventures | Discount Rate | Income Approach Valuation Technique | Retail | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Discount Rate | 10.40% |
Terminal Capitalization Rate | 8.50% |
Maximum | Real Estate Properties and Joint Ventures | Direct Capitalization, Overall Capitalization Rate | Income Approach Valuation Technique | Office | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Overall Capitalization Rate | 7.00% |
Maximum | Real Estate Properties and Joint Ventures | Direct Capitalization, Overall Capitalization Rate | Income Approach Valuation Technique | Industrial | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Overall Capitalization Rate | 7.50% |
Maximum | Real Estate Properties and Joint Ventures | Direct Capitalization, Overall Capitalization Rate | Income Approach Valuation Technique | Residential | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Overall Capitalization Rate | 5.50% |
Maximum | Real Estate Properties and Joint Ventures | Direct Capitalization, Overall Capitalization Rate | Income Approach Valuation Technique | Retail | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Overall Capitalization Rate | 8.30% |
Maximum | Mortgage Loans Payable | Discount Rate | Residential | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Loan-to-Value Ratio | 61.20% |
Equivalency Rate | 3.60% |
Maximum | Mortgage Loans Payable | Discount Rate | Retail | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Loan-to-Value Ratio | 51.60% |
Equivalency Rate | 4.00% |
Maximum | Mortgage Loans Payable | Discount Rate | Office and Industrial | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Loan-to-Value Ratio | 71.00% |
Equivalency Rate | 4.70% |
Maximum | Mortgage Loans Payable | Net Present Value | Residential | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Loan-to-Value Ratio | 61.20% |
Weighted Average Cost of Capital Risk Premium Multiple | 1.50% |
Maximum | Mortgage Loans Payable | Net Present Value | Retail | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Loan-to-Value Ratio | 51.60% |
Weighted Average Cost of Capital Risk Premium Multiple | 1.30% |
Maximum | Mortgage Loans Payable | Net Present Value | Office and Industrial | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Loan-to-Value Ratio | 71.00% |
Weighted Average Cost of Capital Risk Premium Multiple | 1.60% |
Maximum | Loans Receivable | Discount Rate | Office, Retail and Storage | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Loan-to-Value Ratio | 79.20% |
Equivalency Rate | 8.30% |
Weighted Average | Real Estate Properties and Joint Ventures | Discount Rate | Income Approach Valuation Technique | Office | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Discount Rate | 6.50% |
Terminal Capitalization Rate | 5.50% |
Weighted Average | Real Estate Properties and Joint Ventures | Discount Rate | Income Approach Valuation Technique | Industrial | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Discount Rate | 6.70% |
Terminal Capitalization Rate | 5.60% |
Weighted Average | Real Estate Properties and Joint Ventures | Discount Rate | Income Approach Valuation Technique | Residential | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Discount Rate | 6.20% |
Terminal Capitalization Rate | 4.80% |
Weighted Average | Real Estate Properties and Joint Ventures | Discount Rate | Income Approach Valuation Technique | Retail | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Discount Rate | 6.40% |
Terminal Capitalization Rate | 5.20% |
Weighted Average | Real Estate Properties and Joint Ventures | Direct Capitalization, Overall Capitalization Rate | Income Approach Valuation Technique | Office | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Overall Capitalization Rate | 4.70% |
Weighted Average | Real Estate Properties and Joint Ventures | Direct Capitalization, Overall Capitalization Rate | Income Approach Valuation Technique | Industrial | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Overall Capitalization Rate | 5.00% |
Weighted Average | Real Estate Properties and Joint Ventures | Direct Capitalization, Overall Capitalization Rate | Income Approach Valuation Technique | Residential | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Overall Capitalization Rate | 4.20% |
Weighted Average | Real Estate Properties and Joint Ventures | Direct Capitalization, Overall Capitalization Rate | Income Approach Valuation Technique | Retail | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Overall Capitalization Rate | 4.70% |
Weighted Average | Mortgage Loans Payable | Discount Rate | Residential | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Loan-to-Value Ratio | 41.40% |
Equivalency Rate | 3.30% |
Weighted Average | Mortgage Loans Payable | Discount Rate | Retail | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Loan-to-Value Ratio | 31.30% |
Equivalency Rate | 3.50% |
Weighted Average | Mortgage Loans Payable | Discount Rate | Office and Industrial | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Loan-to-Value Ratio | 43.40% |
Equivalency Rate | 3.90% |
Weighted Average | Mortgage Loans Payable | Net Present Value | Residential | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Loan-to-Value Ratio | 41.40% |
Weighted Average Cost of Capital Risk Premium Multiple | 1.30% |
Weighted Average | Mortgage Loans Payable | Net Present Value | Retail | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Loan-to-Value Ratio | 31.30% |
Weighted Average Cost of Capital Risk Premium Multiple | 1.20% |
Weighted Average | Mortgage Loans Payable | Net Present Value | Office and Industrial | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Loan-to-Value Ratio | 43.40% |
Weighted Average Cost of Capital Risk Premium Multiple | 1.30% |
Weighted Average | Loans Receivable | Discount Rate | Office, Retail and Storage | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Loan-to-Value Ratio | 75.80% |
Equivalency Rate | 6.30% |