EARNINGS PER COMMON SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings (loss) per common share
Net income (loss)	$ (65,382)	$ 38,401	$ (123,167)	$ 324,227
Less: Preferred share dividends	7,563	10,656	22,688	31,969
Net income (loss) available (attributable) to common shareholders	$ (72,945)	$ 27,745	$ (145,855)	$ 292,258
Weighted average common shares outstanding (in shares)	84,308	83,947	84,235	83,872
Earnings (loss) per common share (in usd per share)	$ (0.87)	$ 0.33	$ (1.73)	$ 3.48
Earnings (loss) per diluted common share
Net income (loss) available (attributable) to common shareholders	$ (72,945)	$ 27,745	$ (145,855)	$ 292,258
Weighted average common shares outstanding (in shares)	84,308	83,947	84,235	83,872
Share-based compensation plans (in shares)	0	635	0	548
Weighted average diluted common shares outstanding (in shares)	84,308	84,582	84,235	84,420
Earnings (loss) per diluted common share (in usd per share)	$ (0.87)	$ 0.33	$ (1.73)	$ 3.46
Weighted average anti-dilutive shares excluded from the dilutive computation (in shares)	859	9	1,019	204