PREFERRED STOCK - Summary of Preferred Stock (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2020 USD ($) shares
Beginning balance	$ 245,531
Paid-in-kind dividends	14,506
Ending balance	260,037
Series C Preferred Stock
Beginning balance	$ 99,303
Beginning balance (in shares) | shares	125,000
Paid-in-kind dividends	$ 7,328
Ending balance	$ 106,631
Ending balance (in shares) | shares	125,000
Series D Preferred Stock
Beginning balance	$ 29,082
Beginning balance (in shares) | shares	39,254
Paid-in-kind dividends	$ 1,811
Ending balance	$ 30,893
Ending balance (in shares) | shares	39,254
Series E Preferred Stock
Beginning balance	$ 66,285
Beginning balance (in shares) | shares	60,000
Paid-in-kind dividends	$ 2,674
Ending balance	$ 68,959
Ending balance (in shares) | shares	60,000
Series F Preferred Stock
Beginning balance	$ 50,861
Beginning balance (in shares) | shares	55,000
Paid-in-kind dividends	$ 2,693
Ending balance	$ 53,554
Ending balance (in shares) | shares	55,000