Equity, Capital and Other Interests - Changes in Issued and Outstanding Common Shares and Units (Details) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Equity Capital And Other Interests [Abstract]
Common Stock, Shares, Outstanding	368,018,082	365,870,924	364,755,444
Common Shares Issued:
Conversion of OP Units	131,477	1,149,284	88,838
Exercise of share options	1,056,388	846,137	815,044
Employee Share Purchase Plan (ESPP)	75,414	68,286	63,909
Restricted share grants, net	123,800	83,451	147,689
Common Stock, Shares, Outstanding	369,405,161	368,018,082	365,870,924
Units
Total Units Outstanding	13,768,438	14,626,075	14,427,164
Restricted unit grants, net	267,074	291,647	287,749
Conversion of OP Units to Common Shares	(131,477)	(1,149,284)	(88,838)
Total Units Outstanding	13,904,035	13,768,438	14,626,075
Common Shares And Units Outstanding	383,309,196	381,786,520	380,496,999
Units Ownership Interest in Operating Partnership	3.60%	3.60%	3.80%