The Bonds that are subject to interest rate cap agreements.

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Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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Average fixed interest rate related to the group of interest rate derivatives.

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Fair value, before 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 elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

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Fair value of the assets less the liabilities of a derivative or group of derivatives.

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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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Nominal or face amount used to calculate payment on derivative.

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The number of derivative instruments of a particular group held by the entity.

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Amount, after tax and reclassification, of gain (loss) from derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

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Including the current and noncurrent portions, carrying value as of the balance sheet date of uncollateralized debt obligations (with maturities initially due after one year or beyond the operating cycle if longer).

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Derivative Instruments and Hedging Activities (Details)	1 Months Ended	12 Months Ended
Derivative Instruments and Hedging Activities (Details)	Nov. 30, 2016 USD ($)	Dec. 31, 2020 USD ($) instrument	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 instrument	Dec. 31, 2016 instrument	Oct. 31, 2016 USD ($)
Derivative [Line Items]
Unsecured debt, net		$ 5,607,985,000	$ 4,763,206,000
Hedge ineffectiveness related to cash flow hedges		(4,148,000)	(2,948,000)	$ 7,824,000
Total return swap income		10,733,000	8,446,000	8,707,000
Designated as Hedging Instrument
Derivative [Line Items]
Hedge ineffectiveness related to cash flow hedges		0	(200,000)	(100,000)
Not Designated as Hedging Instrument
Derivative [Line Items]
Total return swap income		$ 10,700,000	8,400,000	$ 8,700,000
Interest Rate Swap \| Designated as Hedging Instrument
Derivative [Line Items]
Number of derivative instruments held \| instrument		5			1	4
Average fixed interest rate		2.30%
Derivative fair value		$ (2,400,000)	800,000
Aggregate carrying value of the interest rate swap contracts		2,400,000	200,000
Interest Rate Swap \| Designated as Hedging Instrument \| Prepaid Expenses and Other Assets
Derivative [Line Items]
Derivative fair value		0	1,000,000.0
Interest Rate Cap \| Not Designated as Hedging Instrument
Derivative [Line Items]
Derivative notional amount		0	0
Derivative fair value		$ 0	0
Total Return Swap Callable \| Not Designated as Hedging Instrument
Derivative [Line Items]
Number of derivative instruments held \| instrument		4
Total Return Swap \| Not Designated as Hedging Instrument
Derivative [Line Items]
Derivative fair value		$ 0
Variable Rate Term Loan
Derivative [Line Items]
Unsecured debt, net	$ 350,000,000.0	$ 550,000,000.0	$ 350,000,000.0				$ 225,000,000.0
Debt instrument, term	5 years
Basis spread on rate	0.95%
Variable Rate Term Loan \| Interest Rate Swap
Derivative [Line Items]
Number of derivative instruments held \| instrument		5
Variable Rate Term Loan \| Interest Rate Swap \| Designated as Hedging Instrument
Derivative [Line Items]
Derivative notional amount		$ 175,000,000.0
Variable Rate Mortgage Notes Payable
Derivative [Line Items]
Derivative notional amount		254,800,000
Bond subject to interest rate caps		254,800,000
Mortgage Notes Payable \| Total Return Swap Callable \| Not Designated as Hedging Instrument
Derivative [Line Items]
Derivative notional amount		225,100,000
Mortgage Notes Payable, Real Estate Held-For-Sale \| Total Return Swap Callable \| Not Designated as Hedging Instrument
Derivative [Line Items]
Derivative notional amount		$ 29,700,000