Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Basic earnings per share:
Net income	$ 14,047	$ 167,778	$ 163,852	$ 319,719
Weighted average common shares outstanding - basic (in shares)	338,593	355,734	341,323	355,694
Basic earnings per share (in dollars per share)	$ 0.04	$ 0.47	$ 0.48	$ 0.90
Diluted earnings per share:
Net income	$ 14,047	$ 167,778	$ 163,852	$ 319,719
Diluted income available to common shareholders	$ 14,047	$ 172,344	$ 172,984	$ 328,851
Weighted average common shares outstanding - basic (in shares)	338,593	355,734	341,323	355,694
Effect of dilutive securities:
Weighted average common shares outstanding - diluted (in shares)	339,661	376,603	362,003	376,635
Diluted earnings per share (in dollars per share)	$ 0.04	$ 0.46	$ 0.48	$ 0.87
Antidilutive securities excluded from computation of EPS amount	19,100
Effective income tax rate	21.00%	21.00%	21.00%	21.00%
9% Convertible Junior Subordinated Debentures
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Stated interest rate	9.00%		9.00%
Diluted earnings per share:
Dilutive securities	$ 0	$ 4,566	$ 9,132	$ 9,132
Effect of dilutive securities:
Dilutive securities (in shares)	0	19,028	19,129	19,028
Unvested RSUs
Effect of dilutive securities:
Unvested RSUs (in shares)	1,068	1,841	1,551	1,913