Annual report pursuant to Section 13 and 15(d)

EQUITY-BASED AWARDS - Time-Based LTIP Units Activity (Details)

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EQUITY-BASED AWARDS - Time-Based LTIP Units Activity (Details) - Time-Based LTIP Unit [Member] - $ / shares
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Number of LTIP units      
Unvested units at beginning of year (in shares) 294,529 236,265 509,166
Granted (in shares) 128,051 177,546 6,000
Vested (in shares) (194,814) (119,282) (278,901)
Unvested units at end of year (in shares) 227,766 294,529 236,265
Weighted Average Grant-Date Fair Value      
Unvested at beginning of year (in dollars per share) $ 14.74 $ 10.41 $ 10.07
Granted (in dollars per share) 22.89 17.59 13.00
Vested (in dollars per share) 13.43 10.41 9.84
Unvested at end of year (in dollars per share) $ 20.37 $ 14.74 $ 10.41