CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (Parenthetical) - $ / shares
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY      
Distributions - common stock, Cash per share (in dollars per share) $ 1.66 $ 1.58 $ 1.50