Net Income per Common Share - Reconciliation of denominator in net income per share computation (Details) - shares	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Earnings Per Share [Abstract]
Weighted average shares used for the basic net income per share computation (in shares)	311,032,972	284,928,969	307,293,949	284,469,689
Incremental shares from share-based compensation (in shares)	289,190	126,265	286,178	137,625
Weighted average partnership common units convertible to common shares that were dilutive (in shares)	0	317,022	0	317,022
Weighted average shares used for diluted net income per share computation (in shares)	311,322,162	285,372,256	307,580,127	284,924,336
Unvested shares from share-based compensation
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation (in shares)	25,171	237,861	29,069	164,111
Convertible common partnership units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation (in shares)	463,119	359,980	420,679	207,948

Incremental Common Shares Attributable To Dilutive Effect Of Partnership Common Units

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Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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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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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

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The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

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Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

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