EQUITY STRUCTURE AND ACCOUNTS - Tax Treatment of Aggregate Distributions Per Share of Common Stock Paid (Details) - $ / shares																								3 Months Ended								9 Months Ended		10 Months Ended	12 Months Ended
	Jan. 03, 2018	Nov. 07, 2017	Oct. 02, 2017	Sep. 01, 2017	Jul. 03, 2017	Jun. 01, 2017	Apr. 03, 2017	Mar. 01, 2017	Jan. 24, 2017	Dec. 02, 2016	Oct. 03, 2016	Sep. 01, 2016	Jul. 01, 2016	Jun. 01, 2016	Apr. 01, 2016	Jan. 21, 2016	Dec. 01, 2015	Oct. 01, 2015	Sep. 01, 2015	Jul. 01, 2015	Jun. 08, 2015	Apr. 15, 2015	Mar. 12, 2015	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Jan. 03, 2018	Jan. 21, 2016	Jan. 24, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Class of Stock [Line Items]
Dividends per share of common stock (in dollars per share)																								$ 0.315	$ 0.3	$ 0.3	$ 0.3	$ 0.46	$ 0.275	$ 0.275	$ 0.275
Class A common stock
Class of Stock [Line Items]
Dividends per share of common stock (in dollars per share)		$ 0.315		$ 0.3		$ 0.3		$ 0.3		$ 0.46		$ 0.275		$ 0.275	$ 0.275		$ 1.45		$ 0.275		$ 0.25		$ 0.25												$ 1.215	$ 1.285	$ 2.225
Subsequent Event | Class A common stock
Class of Stock [Line Items]
Dividend per Share (in dollars per share)	$ 0.315
Tax Year 2017 | Class A common stock
Class of Stock [Line Items]
Dividend per Share (in dollars per share)			$ 0.3		$ 0.3		$ 0.3		$ 0.059
Ordinary Dividends (in dollars per share)			0.276		0.276		0.276		0.054
Qualified Dividends (in dollars per share)			0		0		0		0
Capital Gain (in dollars per share)			0.024		0.024		0.024		0.005
Unrecaptured 1250 Gain (in dollars per share)			$ 0		$ 0		$ 0		0
Tax Year 2017 | Subsequent Event | Class A common stock
Class of Stock [Line Items]
Dividend per Share (in dollars per share)	0.265																															$ 1.224
Ordinary Dividends (in dollars per share)	0.244																															1.126
Qualified Dividends (in dollars per share)	0																															0
Capital Gain (in dollars per share)	0.021																															0.098
Unrecaptured 1250 Gain (in dollars per share)	0																															$ 0
Tax Year 2018 | Subsequent Event | Class A common stock
Class of Stock [Line Items]
Dividend per Share (in dollars per share)	$ 0.05
Tax Year 2016 | Class A common stock
Class of Stock [Line Items]
Dividend per Share (in dollars per share)									0.401		$ 0.275		$ 0.275		0.275																			$ 1.226
Ordinary Dividends (in dollars per share)									0.37		0.254		0.254		0.254																			1.132
Qualified Dividends (in dollars per share)									0		0		0		0																			0
Capital Gain (in dollars per share)									0.031		0.021		0.021		0.021																			0.094
Unrecaptured 1250 Gain (in dollars per share)									$ 0		$ 0		$ 0		$ 0																			$ 0
Tax Year 2015 | Class A common stock
Class of Stock [Line Items]
Dividend per Share (in dollars per share)																$ 1.45		$ 0.275		$ 0.25		$ 0.25											$ 2.225
Ordinary Dividends (in dollars per share)																1.306		0.275		0.25		0.25											2.081
Qualified Dividends (in dollars per share)																0.156		0.275		0.25		0.25											0.931
Capital Gain (in dollars per share)																0.144		0		0		0											0.144
Unrecaptured 1250 Gain (in dollars per share)																$ 0.020		$ 0		$ 0		$ 0											$ 0.02