EQUITY STRUCTURE AND ACCOUNTS - Changes in Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
AOCI Attributable to Parent [Roll Forward]
December 31, 2015			$ (3,556)
Other comprehensive income (loss)	$ 27,468	$ (38,615)	61,851	$ (20,111)	$ (36,545)
Exchange of noncontrolling interest for common stock			(772)		0
June 30, 2016	31,956		31,956		(3,556)
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent [Roll Forward]
December 31, 2015			(3,556)
Other comprehensive income (loss)			35,295		(20,046)
Exchange of noncontrolling interest for common stock			(122)		645
Rebalancing of ownership percentage between Company and Operating Partnership			339
June 30, 2016	31,956		31,956		(3,556)
Accumulated Other Comprehensive Income of Noncontrolling Interests
AOCI Attributable to Parent [Roll Forward]
December 31, 2015			(2,839)
Other comprehensive income (loss)			26,556
Exchange of noncontrolling interest for common stock			122
Rebalancing of ownership percentage between Company and Operating Partnership			(339)
June 30, 2016	23,500		23,500		(2,839)
Total Accumulated Other Comprehensive Income
AOCI Attributable to Parent [Roll Forward]
December 31, 2015			(6,395)
Other comprehensive income (loss)			61,851
Exchange of noncontrolling interest for common stock			0
Rebalancing of ownership percentage between Company and Operating Partnership			0
June 30, 2016	$ 55,456		$ 55,456		$ (6,395)