EQUITY STRUCTURE AND ACCOUNTS - Changes in Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
AOCI Attributable to Parent [Roll Forward]
Balance at the beginning of the year	$ 1,365
Other comprehensive income (loss)	4,751	$ 34,383	$ 8,519
Exchange of noncontrolling interest for common stock	(884)		0
Balance at the end of the year	4,834		1,365
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent [Roll Forward]
Balance at the beginning of the year	1,365	(3,556)	(3,556)
Other comprehensive income (loss)	3,117	19,467	3,420
Exchange of noncontrolling interest for common stock	403	(122)	1,202
Rebalancing of ownership percentage between Company and Operating Partnership	(51)	350
Balance at the end of the year	4,834	16,139	1,365
Accumulated Other Comprehensive Income of Noncontrolling Interests
AOCI Attributable to Parent [Roll Forward]
Balance at the beginning of the year	761	(2,839)	(2,839)
Other comprehensive income (loss)	1,634	14,916
Exchange of noncontrolling interest for common stock	(403)	122
Rebalancing of ownership percentage between Company and Operating Partnership	51	(350)
Balance at the end of the year	2,043	11,849	761
Total Accumulated Other Comprehensive Income
AOCI Attributable to Parent [Roll Forward]
Balance at the beginning of the year	2,126	(6,395)	(6,395)
Other comprehensive income (loss)	4,751	34,383
Exchange of noncontrolling interest for common stock	0	0
Rebalancing of ownership percentage between Company and Operating Partnership	0	0
Balance at the end of the year	$ 6,877	$ 27,988	$ 2,126