Shareholders' Equity, Noncontrolling Interests and Other Comprehensive Income - Common Shares and Units - Additional Information (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Restricted shares
Class Of Stock [Line Items]
Restricted stock, shares canceled for tax withholding for share based compensation (in shares)	2,468		3,288
LTIP Units and Restricted Stock
Class Of Stock [Line Items]
Unit based compensation	$ 3.7	$ 4.3	$ 8.4

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.

No definition available.

Name:	us-gaap_ClassOfStockLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration