CAPITAL STOCK - Summary of Dividend Distribution Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Jun. 30, 2019
Dividends Payable [Line Items]
Dividends and dividend equivalents declared on common stock and share-based awards	$ 359,736	$ 365,488	$ 1,158,629	$ 1,062,685
Distributions declared per common share (in dollars per share)	$ 0.25	$ 0.30	$ 0.80	$ 0.90
Distributions paid to common stockholders after period end	$ 359,491	$ 102,811	$ 359,491	$ 102,811
Distributions paid per common share after period end (in dollars per share)	$ 0.25	$ 0.08	$ 0.25	$ 0.08
Cumulative and undeclared dividends					$ 300
Series C
Dividends Payable [Line Items]
Preferred dividends declared	$ 742	$ 3,336	$ 7,414	$ 10,987
Preferred series dividends declared (in dollars per share)	$ 0.106	$ 0.477	$ 1.060	$ 1.430
Series D
Dividends Payable [Line Items]
Preferred dividends declared	$ 8,625	$ 8,625	$ 25,875	$ 25,875
Preferred series dividends declared (in dollars per share)	$ 0.469	$ 0.469	$ 1.407	$ 1.406
Series E
Dividends Payable [Line Items]
Preferred dividends declared	$ 0	$ 0	$ 0	$ 2,253
Preferred series dividends declared (in dollars per share)	$ 0	$ 0	$ 0	$ 0.196
Series F
Dividends Payable [Line Items]
Preferred dividends declared	$ 12,510	$ 12,510	$ 37,530	$ 37,530
Preferred series dividends declared (in dollars per share)	$ 0.434	$ 0.434	$ 1.303	$ 1.303
Series G
Dividends Payable [Line Items]
Preferred dividends declared	$ 6,906	$ 6,906	$ 20,718	$ 19,875
Preferred series dividends declared (in dollars per share)	$ 0.406	$ 0.406	$ 1.219	$ 1.169
Series H
Dividends Payable [Line Items]
Preferred dividends declared	$ 0	$ 298	$ 1,862	$ 298
Preferred series dividends declared (in dollars per share)	$ 0	$ 0.135	$ 0.846	$ 0.135
Series I
Dividends Payable [Line Items]
Preferred dividends declared	$ 7,668	$ 0	$ 7,668	$ 0
Preferred series dividends declared (in dollars per share)	$ 0.436	$ 0	$ 0.436	$ 0
Cumulative and undeclared dividends	$ 300		$ 300