Annual report pursuant to Section 13 and 15(d)

Consolidated Statements of Equity (Parenthetical)

v3.8.0.1
Consolidated Statements of Equity (Parenthetical) - shares
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Balance (in units/ shares) 101,292,299 98,498,651 94,531,512
Conversion of common units to common shares (in shares/units) 339,513 87,000 160,160
Exercise of share options (in units/shares) 5,000   76,474
Restricted common units/shares net of redemptions 179,180 158,912 149,353
Preferred Shares [Member]      
Stock redeemed or called during period (in units/ shares) (6,900,000) (531,667)  
Forward Equity Sale Agreement [Member]      
Shares issued to the public (in units/shares) 1,678,913    
Common Stock Issued to Public Under At-the-Market Program [Member]      
Shares issued to the public (in units/shares) 591,042 3,721,227 890,241