Equity and Earnings Per Common Share - Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended				9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Equity and Earnings Per Common Share
Net income (loss)	$ (289,477)	$ 18,028	$ 14,387	$ 12,805	$ (210,555)	$ 45,220
Less net income attributable to Series B Units		(598)				(1,517)
Less preferred stock dividends	(138)				(304)
Net income (loss) available to common shareholders	$ (289,615)	$ 17,430			$ (210,859)	$ 43,703
Net income (loss) per share-basic and diluted	$ (0.57)	$ 0.09			$ (0.50)	$ 0.23
Weighted average common shares outstanding-basic	506,419	186,208			423,296	186,199
Weighted average common shares outstanding-diluted	506,419	186,208			423,296	186,199