Share-Based Payments - LTIP and Time-Based LTIP Units (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	6 Months Ended
Apr. 30, 2020	Jun. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Compensation expense recognition period (in years)		2 years
Management \| Time-Based Long-Term Incentive Partnership Units
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Equity grants (in shares)		381,504
Weighted average grant-date fair value (in dollars per share)		$ 38.52
Vesting period		4 years
Vesting (as a percent)		25.00%
Compensation expense recognition period (in years)		4 years
Fair value of awards on grant date		$ 14.7
Management \| LTIP Units
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Equity grants (in shares)		90,094
Weighted average grant-date fair value (in dollars per share)		$ 40.13
Fair value of awards on grant date		$ 3.6
Trustees \| LTIP Units
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Equity grants (in shares)	54,607
Fair value of awards on grant date	$ 1.5
Minimum \| LTIP and Time-Based LTIP Units
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Expected volatility		18.00%
Risk-free interest rate		0.30%
Post-grant restriction periods		2 years
Maximum \| LTIP and Time-Based LTIP Units
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Expected volatility		29.00%
Risk-free interest rate		1.50%
Post-grant restriction periods		3 years

The total fair value of shares issued during the period under a deferred compensation arrangement.

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- Definition

Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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- Definition

The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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- Definition

The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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- Definition

The risk-free interest rate assumption that is used in valuing an option on its own shares.

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- Definition

Percentage of vesting of award under share-based payment arrangement.

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- Definition

Expected term of award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(i)
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 14.D.2)
-URI http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809

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