Assets and Liabilities Measured at Fair Value on a Recurring Basis - Schedule of unobservable inputs related to Level 3 fair value measurements (Details) | 3 Months Ended |
Mar. 31, 2017 |
Office | Real Estate Properties and Joint Ventures | Minimum | Discounted Cash Flow Analysis Valuation Technique | Income Approach Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Discount Rate | 5.50% |
Terminal Capitalization Rate | 4.30% |
Office | Real Estate Properties and Joint Ventures | Minimum | Direct Capitalization Valuation Technique | Income Approach Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Overall Capitalization Rate | 3.80% |
Office | Real Estate Properties and Joint Ventures | Maximum | Discounted Cash Flow Analysis Valuation Technique | Income Approach Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Discount Rate | 8.30% |
Terminal Capitalization Rate | 7.30% |
Office | Real Estate Properties and Joint Ventures | Maximum | Direct Capitalization Valuation Technique | Income Approach Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Overall Capitalization Rate | 7.00% |
Office | Real Estate Properties and Joint Ventures | Weighted Average | Discounted Cash Flow Analysis Valuation Technique | Income Approach Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Discount Rate | 6.50% |
Terminal Capitalization Rate | 5.50% |
Office | Real Estate Properties and Joint Ventures | Weighted Average | Direct Capitalization Valuation Technique | Income Approach Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Overall Capitalization Rate | 4.60% |
Industrial | Real Estate Properties and Joint Ventures | Minimum | Discounted Cash Flow Analysis Valuation Technique | Income Approach Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Discount Rate | 5.70% |
Terminal Capitalization Rate | 4.80% |
Industrial | Real Estate Properties and Joint Ventures | Minimum | Direct Capitalization Valuation Technique | Income Approach Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Overall Capitalization Rate | 4.00% |
Industrial | Real Estate Properties and Joint Ventures | Maximum | Discounted Cash Flow Analysis Valuation Technique | Income Approach Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Discount Rate | 8.60% |
Terminal Capitalization Rate | 8.00% |
Industrial | Real Estate Properties and Joint Ventures | Maximum | Direct Capitalization Valuation Technique | Income Approach Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Overall Capitalization Rate | 7.50% |
Industrial | Real Estate Properties and Joint Ventures | Weighted Average | Discounted Cash Flow Analysis Valuation Technique | Income Approach Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Discount Rate | 6.60% |
Terminal Capitalization Rate | 5.50% |
Industrial | Real Estate Properties and Joint Ventures | Weighted Average | Direct Capitalization Valuation Technique | Income Approach Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Overall Capitalization Rate | 4.90% |
Apartment | Real Estate Properties and Joint Ventures | Minimum | Discounted Cash Flow Analysis Valuation Technique | Income Approach Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Discount Rate | 5.30% |
Terminal Capitalization Rate | 3.80% |
Apartment | Real Estate Properties and Joint Ventures | Minimum | Direct Capitalization Valuation Technique | Income Approach Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Overall Capitalization Rate | 3.30% |
Apartment | Real Estate Properties and Joint Ventures | Maximum | Discounted Cash Flow Analysis Valuation Technique | Income Approach Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Discount Rate | 7.30% |
Terminal Capitalization Rate | 6.00% |
Apartment | Real Estate Properties and Joint Ventures | Maximum | Direct Capitalization Valuation Technique | Income Approach Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Overall Capitalization Rate | 5.50% |
Apartment | Real Estate Properties and Joint Ventures | Weighted Average | Discounted Cash Flow Analysis Valuation Technique | Income Approach Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Discount Rate | 6.20% |
Terminal Capitalization Rate | 4.80% |
Apartment | Real Estate Properties and Joint Ventures | Weighted Average | Direct Capitalization Valuation Technique | Income Approach Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Overall Capitalization Rate | 4.20% |
Apartment | Mortgage Loans Payable | Minimum | Discounted Cash Flow Analysis Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Loan to Value Ratio | 29.50% |
Equivalency Rate | 2.90% |
Apartment | Mortgage Loans Payable | Minimum | Net Present Value Valuation Technique | |
Fair Value, Assets 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% |
Apartment | Mortgage Loans Payable | Maximum | Discounted Cash Flow Analysis Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Loan to Value Ratio | 61.20% |
Equivalency Rate | 3.60% |
Apartment | Mortgage Loans Payable | Maximum | Net Present Value Valuation Technique | |
Fair Value, Assets 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% |
Apartment | Mortgage Loans Payable | Weighted Average | Discounted Cash Flow Analysis Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Loan to Value Ratio | 41.60% |
Equivalency Rate | 3.30% |
Apartment | Mortgage Loans Payable | Weighted Average | Net Present Value Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Loan to Value Ratio | 41.60% |
Weighted Average Cost of Capital Risk Premium Multiple | 1.30% |
Retail | Real Estate Properties and Joint Ventures | Minimum | Discounted Cash Flow Analysis Valuation Technique | Income Approach Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Discount Rate | 5.00% |
Terminal Capitalization Rate | 4.30% |
Retail | Real Estate Properties and Joint Ventures | Minimum | Direct Capitalization Valuation Technique | Income Approach Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Overall Capitalization Rate | 3.80% |
Retail | Real Estate Properties and Joint Ventures | Maximum | Discounted Cash Flow Analysis Valuation Technique | Income Approach Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Discount Rate | 10.40% |
Terminal Capitalization Rate | 8.50% |
Retail | Real Estate Properties and Joint Ventures | Maximum | Direct Capitalization Valuation Technique | Income Approach Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Overall Capitalization Rate | 8.30% |
Retail | Real Estate Properties and Joint Ventures | Weighted Average | Discounted Cash Flow Analysis Valuation Technique | Income Approach Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Discount Rate | 6.40% |
Terminal Capitalization Rate | 5.20% |
Retail | Real Estate Properties and Joint Ventures | Weighted Average | Direct Capitalization Valuation Technique | Income Approach Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Overall Capitalization Rate | 4.70% |
Retail | Mortgage Loans Payable | Minimum | Discounted Cash Flow Analysis Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Loan to Value Ratio | 18.30% |
Equivalency Rate | 3.00% |
Retail | Mortgage Loans Payable | Minimum | Net Present Value Valuation Technique | |
Fair Value, Assets 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% |
Retail | Mortgage Loans Payable | Maximum | Discounted Cash Flow Analysis Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Loan to Value Ratio | 51.10% |
Equivalency Rate | 4.50% |
Retail | Mortgage Loans Payable | Maximum | Net Present Value Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Loan to Value Ratio | 51.10% |
Weighted Average Cost of Capital Risk Premium Multiple | 1.30% |
Retail | Mortgage Loans Payable | Weighted Average | Discounted Cash Flow Analysis Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Loan to Value Ratio | 31.30% |
Equivalency Rate | 3.60% |
Retail | Mortgage Loans Payable | Weighted Average | Net Present Value Valuation Technique | |
Fair Value, Assets 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% |
Office and Industrial | Mortgage Loans Payable | Minimum | Discounted Cash Flow Analysis Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Loan to Value Ratio | 38.50% |
Equivalency Rate | 3.70% |
Office and Industrial | Mortgage Loans Payable | Minimum | Net Present Value Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Loan to Value Ratio | 38.50% |
Weighted Average Cost of Capital Risk Premium Multiple | 1.20% |
Office and Industrial | Mortgage Loans Payable | Maximum | Discounted Cash Flow Analysis Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Loan to Value Ratio | 68.40% |
Equivalency Rate | 4.60% |
Office and Industrial | Mortgage Loans Payable | Maximum | Net Present Value Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Loan to Value Ratio | 68.40% |
Weighted Average Cost of Capital Risk Premium Multiple | 1.50% |
Office and Industrial | Mortgage Loans Payable | Weighted Average | Discounted Cash Flow Analysis Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Loan to Value Ratio | 43.70% |
Equivalency Rate | 3.90% |
Office and Industrial | Mortgage Loans Payable | Weighted Average | Net Present Value Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Loan to Value Ratio | 43.70% |
Weighted Average Cost of Capital Risk Premium Multiple | 1.30% |
Office, Retail and Storage | Loans Receivable | Minimum | Discounted Cash Flow Analysis Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Loan to Value Ratio | 58.90% |
Equivalency Rate | 4.20% |
Office, Retail and Storage | Loans Receivable | Maximum | Discounted Cash Flow Analysis Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Loan to Value Ratio | 79.20% |
Equivalency Rate | 8.30% |
Office, Retail and Storage | Loans Receivable | Weighted Average | Discounted Cash Flow Analysis Valuation Technique | |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Loan to Value Ratio | 75.90% |
Equivalency Rate | 6.30% |