Equity and Earnings Per Common Share - Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Equity and Earnings Per Common Share
Net income (loss)	$ 88,441	$ (392,933)	$ 69,274	$ (304,492)	$ 78,922
Less preferred stock dividends	(137)		(139)	(275)	(168)
Net income (loss) available to common shareholders	$ 88,304		$ 69,135	$ (304,767)	$ 78,754
Net income (loss) per share-basic (in dollars per share)	$ 0.19		$ 0.14	$ (0.63)	$ 0.21
Net income (loss) per share-diluted (in dollars per share)	$ 0.18		$ 0.14	$ (0.63)	$ 0.21
Weighted average common shares outstanding-basic	476,836		506,816	479,969	381,045
Weighted average common shares outstanding-diluted	478,837		507,767	479,969	382,026