Net Income (Loss) per Common Share - Reconciliation of Net Income (Loss) and Shares Used in Calculating Basic and Diluted Earnings Per Share (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Earnings Per Share [Abstract]
Net Income (Loss)	$ 108,681	$ (60,955)	$ (183,250)	$ (114,381)	$ (211,979)	$ 47,704	$ 13,562	$ 44,747	$ (249,905)	$ (105,966)	$ 181,154
Less: Preferred dividends	(3,691)	(3,410)	(4,274)	(4,259)	(4,261)	(4,259)	(4,259)	(4,253)	(15,634)	(17,032)	(15,880)
Net Income (Loss) available (related) to common stockholders	$ 104,990	$ (64,365)	$ (187,524)	$ (118,640)	$ (216,240)	$ 43,445	$ 9,303	$ 40,494	$ (265,539)	$ (122,998)	$ 165,274
Basic (in shares)	58,902	59,077	59,654	53,630	42,656	42,047	41,912	41,887	57,833	42,128	39,170
Add: Effect of dilutive non-vested awards, assumed vested (in shares)									0	0	472
Weighted average common shares outstanding – diluted (in shares)	59,149	59,077	59,654	53,630	42,656	42,435	42,328	42,331	57,833	42,128	39,642