EQUITY STRUCTURE AND ACCOUNTS - Dividends Declared (Details) - $ / shares														3 Months Ended								12 Months Ended
	Nov. 26, 2019	Aug. 22, 2019	May 30, 2019	Feb. 27, 2019	Jan. 24, 2019	Oct. 30, 2018	Sep. 05, 2018	May 30, 2018	Feb. 27, 2018	Nov. 07, 2017	Sep. 01, 2017	Jun. 01, 2017	Mar. 01, 2017	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Class A Common Stock
Class of Stock [Line Items]
Dividends per share of Class A common stock (in dollars per share)	$ 0.340	$ 0.340	$ 0.340	$ 0.340	$ 0.570	$ 0.570	$ 0.325	$ 0.325	$ 0.315	$ 0.315	$ 0.300	$ 0.300	$ 0.300	$ 0.340	$ 0.340	$ 0.340	$ 0.340	$ 0.570	$ 0.325	$ 0.325	$ 0.315	$ 1.360	$ 1.535	$ 1.215