Fair Value Assets Measured On Recurring Basis.

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Fair Value Liabilities Measured On Recurring Basis Fixed Rate Secured Debt Instruments.

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Fair Value Liabilities Measured On Recurring Basis Variable Rate Secured Debt Instruments.

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Fair Value Liabilities Measured On Recurring Basis Variable Rate Unsecured Debt Instruments.

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No definition available.

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Fair value of fixed rate secured debt instruments as of the balance sheet date.

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Secured debt including debt on real estate held for sale.

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Fair value of unsecured debt instruments as of the balance sheet date.

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Fair value of variable rate secured debt instruments as of the balance sheet date.

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Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Fair value, after offset of derivative liability, of financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, before offset against an obligation to return collateral under a master netting arrangement. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

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Fair value, after offset of derivative asset, of financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, elected not to be and before offset against a right to receive collateral under a master netting arrangement. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

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Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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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.

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Fair value of financial and nonfinancial obligations.

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The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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Fair value portion of an agreement for an unconditional promise by the maker to pay the holder a definite sum of money at a future date.

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Net amount of the investment in a contractual right to receive money on demand or on fixed or determinable dates that is recognized as an asset in the creditor's statement of financial position. Examples include, but are not limited to, credit card receivables, notes receivable and receivables relating to lessor's rights to payments from leases other than operating leases that have been recorded as assets. Excludes trade accounts receivable with contractual maturity of one year or less and arose from the sale of goods or services.

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As of the reporting date, the aggregate carrying amount of all noncontrolling interests which are redeemable by the (parent) entity (1) at a fixed or determinable price on a fixed or determinable date, (2) at the option of the holder of the noncontrolling interest, or (3) upon occurrence of an event that is not solely within the control of the (parent) entity. This item includes noncontrolling interest holder's ownership (or holders' ownership) regardless of the type of equity interest (common, preferred, other) including all potential organizational (legal) forms of the investee entity.

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As of the reporting date, the carrying amount of noncontrolling interests which are redeemable by the (parent) entity (1) at a fixed or determinable price on a fixed or determinable date, (2) at the option of the holder of the noncontrolling interest, or (3) upon occurrence of an event that is not solely within the control of the (parent) entity. The noncontrolling interest holder's ownership (or holders' ownership) may be in the form of common shares (regardless of class), limited partnership units (regardless of class), non-preferential membership interests, or any other form of common equity regardless of investee entity legal form.

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Fair Value of Derivatives and Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing Receivable, Net	$ 16,694	$ 14,369
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Derivative Asset	13	88
Derivative Liability	2,112	10,368
Secured debt instruments - variable rate
Long-term Line of Credit	2,300	1,900
Unsecured debt instruments
Redeemable Noncontrolling Interest, Equity, Carrying Amount	946,436	282,480
Redeemable non-controlling interests in the Operating Partnership and DownREIT Partnership	946,436	282,480	$ 217,597
Carrying Amount \| Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing Receivable, Net	16,694	14,369
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Total assets	16,707	14,457
Unsecured debt instruments
Total liabilities	3,590,829	3,593,473
Carrying Amount \| Interest rate contracts \| Fair Value, Measurements, Recurring
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Derivative Liability		10,368
Carrying Amount \| Senior unsecured notes \| Fair Value, Measurements, Recurring
Unsecured debt instruments
Unsecured debt instruments	2,056,223	2,069,076
Fair Value \| Fair Value, Measurements, Recurring
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Notes receivable	16,938	14,808
Total assets	16,951	14,896
Unsecured debt instruments
Total liabilities	3,673,283	3,721,512
Redeemable non-controlling interests in the Operating Partnership and DownREIT Partnership	946,436	282,480
Fair Value \| Interest rate contracts \| Fair Value, Measurements, Recurring
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Derivative Asset Designated as Hedging Instrument, Fair Value	13	88
Derivatives - Interest rate contracts	2,112	10,368
Fair Value \| Mortgages [Member] \| Fair Value, Measurements, Recurring
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	448,019	415,663
Secured debt instruments - variable rate
Secured debt instruments - variable rate	31,337	31,337
Fair Value \| Tax-exempt secured notes payable \| Fair Value, Measurements, Recurring
Secured debt instruments - variable rate
Secured debt instruments - variable rate	94,700	94,700
Fair Value \| Fannie Mae credit facilities \| Fair Value, Measurements, Recurring
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	539,050	606,623
Secured debt instruments - variable rate
Secured debt instruments - variable rate	299,378	266,196
Unsecured debt instruments
Unsecured debt instruments	150,000	152,500
Fair Value \| Senior unsecured notes \| Fair Value, Measurements, Recurring
Unsecured debt instruments
Unsecured debt instruments	2,108,687	2,144,125
Fair Value \| Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) \| Fair Value, Measurements, Recurring
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Notes receivable	0	0
Total assets	0	0
Unsecured debt instruments
Total liabilities	0	0
Redeemable non-controlling interests in the Operating Partnership and DownREIT Partnership	0	0
Fair Value \| Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) \| Interest rate contracts \| Fair Value, Measurements, Recurring
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Derivative Asset Designated as Hedging Instrument, Fair Value	0	0
Derivatives - Interest rate contracts	0	0
Fair Value \| Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) \| Mortgages [Member] \| Fair Value, Measurements, Recurring
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	0	0
Secured debt instruments - variable rate
Secured debt instruments - variable rate	0	0
Fair Value \| Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) \| Tax-exempt secured notes payable \| Fair Value, Measurements, Recurring
Secured debt instruments - variable rate
Secured debt instruments - variable rate	0	0
Fair Value \| Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) \| Fannie Mae credit facilities \| Fair Value, Measurements, Recurring
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	0	0
Secured debt instruments - variable rate
Secured debt instruments - variable rate	0	0
Fair Value \| Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) \| Commercial bank \| Fair Value, Measurements, Recurring
Unsecured debt instruments
Unsecured debt instruments	0	0
Fair Value \| Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) \| Senior unsecured notes \| Fair Value, Measurements, Recurring
Unsecured debt instruments
Unsecured debt instruments	0	0
Fair Value \| Significant Other Observable Inputs (Level 2) \| Fair Value, Measurements, Recurring
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Notes receivable	0	0
Total assets	13	88
Unsecured debt instruments
Total liabilities	2,112	10,368
Redeemable non-controlling interests in the Operating Partnership and DownREIT Partnership	946,436	282,480
Fair Value \| Significant Other Observable Inputs (Level 2) \| Interest rate contracts \| Fair Value, Measurements, Recurring
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Derivative Asset Designated as Hedging Instrument, Fair Value	13	88
Derivatives - Interest rate contracts	2,112	10,368
Fair Value \| Significant Other Observable Inputs (Level 2) \| Mortgages [Member] \| Fair Value, Measurements, Recurring
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	0	0
Secured debt instruments - variable rate
Secured debt instruments - variable rate	0	0
Fair Value \| Significant Other Observable Inputs (Level 2) \| Tax-exempt secured notes payable \| Fair Value, Measurements, Recurring
Secured debt instruments - variable rate
Secured debt instruments - variable rate	0	0
Fair Value \| Significant Other Observable Inputs (Level 2) \| Fannie Mae credit facilities \| Fair Value, Measurements, Recurring
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	0	0
Secured debt instruments - variable rate
Secured debt instruments - variable rate	0	0
Fair Value \| Significant Other Observable Inputs (Level 2) \| Commercial bank \| Fair Value, Measurements, Recurring
Unsecured debt instruments
Unsecured debt instruments	0	0
Fair Value \| Significant Other Observable Inputs (Level 2) \| Senior unsecured notes \| Fair Value, Measurements, Recurring
Unsecured debt instruments
Unsecured debt instruments	0	0
Fair Value \| Significant Unobservable Inputs (Level 3) \| Fair Value, Measurements, Recurring
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Notes receivable	16,938	14,808
Total assets	16,938	14,808
Unsecured debt instruments
Total liabilities	3,671,171	3,711,144
Redeemable non-controlling interests in the Operating Partnership and DownREIT Partnership	0	0
Fair Value \| Significant Unobservable Inputs (Level 3) \| Interest rate contracts \| Fair Value, Measurements, Recurring
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Derivative Asset Designated as Hedging Instrument, Fair Value	0	0
Derivatives - Interest rate contracts	0	0
Fair Value \| Significant Unobservable Inputs (Level 3) \| Mortgages [Member] \| Fair Value, Measurements, Recurring
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	448,019	415,663
Secured debt instruments - variable rate
Secured debt instruments - variable rate	31,337	31,337
Fair Value \| Significant Unobservable Inputs (Level 3) \| Tax-exempt secured notes payable \| Fair Value, Measurements, Recurring
Secured debt instruments - variable rate
Secured debt instruments - variable rate	94,700	94,700
Fair Value \| Significant Unobservable Inputs (Level 3) \| Fannie Mae credit facilities \| Fair Value, Measurements, Recurring
Secured debt instruments - fixed rate
Secured debt instruments - fixed rate	539,050	606,623
Secured debt instruments - variable rate
Secured debt instruments - variable rate	299,378	266,196
Fair Value \| Significant Unobservable Inputs (Level 3) \| Commercial bank \| Fair Value, Measurements, Recurring
Unsecured debt instruments
Unsecured debt instruments	150,000	152,500
Fair Value \| Significant Unobservable Inputs (Level 3) \| Senior unsecured notes \| Fair Value, Measurements, Recurring
Unsecured debt instruments
Unsecured debt instruments	2,108,687	2,144,125
Fixed Rate Debt
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Secured Debt Including Debt on Real Estate Held for Sale	952,801	963,713
Variable Rate Debt
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Secured Debt Including Debt on Real Estate Held for Sale	424,144	390,608
Unsecured Revolving Credit Facility due October 2015
Secured debt instruments - variable rate
Long-term Line of Credit	150,000	152,500
Tax-exempt secured notes payable \| Variable Rate Debt \| Carrying Amount \| Tax-exempt secured notes payable \| Fair Value, Measurements, Recurring
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Secured Debt Including Debt on Real Estate Held for Sale	94,700	94,700
Fannie Mae credit facilities \| Fixed Rate Debt \| Carrying Amount \| Fannie Mae credit facilities \| Fair Value, Measurements, Recurring
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Secured Debt Including Debt on Real Estate Held for Sale	514,462	568,086
Fannie Mae credit facilities \| Variable Rate Debt \| Carrying Amount \| Fannie Mae credit facilities \| Fair Value, Measurements, Recurring
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Secured Debt Including Debt on Real Estate Held for Sale	299,378	266,196
Mortgages [Member] \| Fixed Rate Debt \| Carrying Amount \| Mortgages [Member] \| Fair Value, Measurements, Recurring
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Secured Debt Including Debt on Real Estate Held for Sale	442,617	401,210
Mortgages [Member] \| Variable Rate Debt \| Carrying Amount \| Mortgages [Member] \| Fair Value, Measurements, Recurring
Estimated fair values of the financial instruments either recorded or disclosed on a recurring basis
Secured Debt Including Debt on Real Estate Held for Sale	$ 31,337	$ 31,337