Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Basic earnings per share:
Net income	$ 153,051	$ 14,047	$ 303,072	$ 163,852
Weighted average common shares outstanding - basic (in shares)	339,326	338,593	339,116	341,323
Basic earnings per share (in dollars per share)	$ 0.45	$ 0.04	$ 0.89	$ 0.48
Diluted earnings per share:
Net income	$ 153,051	$ 14,047	$ 303,072	$ 163,852
Diluted income available to common shareholders	$ 156,763	$ 14,047	$ 310,495	$ 172,984
Weighted average common shares outstanding - basic (in shares)	339,326	338,593	339,116	341,323
Effect of dilutive securities:
Weighted average common shares outstanding - diluted (in shares)	356,536	339,661	356,461	362,003
Diluted earnings per share (in dollars per share)	$ 0.44	$ 0.04	$ 0.87	$ 0.48
Antidilutive securities excluded from computation of EPS amount (in shares)		19,100
Federal statutory income tax rate (in hundredths)	21.00%	21.00%	21.00%	21.00%
9% Convertible Junior Subordinated Debentures
Diluted earnings per share:
Dilutive securities	$ 3,712	$ 0	$ 7,423	$ 9,132
Effect of dilutive securities:
Dilutive securities (in shares)	15,785	0	15,785	19,129
Stated interest rate	9.00%		9.00%
Unvested RSUs
Effect of dilutive securities:
Unvested RSUs (in shares)	1,425	1,068	1,560	1,551