SUBSEQUENT EVENTS - Additional Information (Details) - USD ($)		3 Months Ended	12 Months Ended
	May 07, 2020	Mar. 31, 2020	Dec. 31, 2019
6.45% Series D Preferred Stock
Subsequent events
Preferred stock, dividend rate		6.45%	6.45%
6.25% Series E Preferred Stock
Subsequent events
Preferred stock, dividend rate		6.25%	6.25%
Subsequent Event | 6.45% Series D Preferred Stock
Subsequent events
Cash dividends declared, preferred stock (in dollars per share)	$ 0.403125
Subsequent Event | 6.25% Series E Preferred Stock
Subsequent events
Cash dividends declared, preferred stock (in dollars per share)	$ 0.390625
Unsecured Debt | $400 Million Revolver | Subsequent Event
Subsequent events
Additional borrowing capacity	$ 150,000,000.0