Earnings Per Share (Net Income Per Share Basic And Diluted) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Numerator:
Net income	$ 307,499	$ 504,446	$ 681,813
Denominator:
Denominator for basic earnings per share - weighted-average shares outstanding (in shares)	124,113,000	123,575,000	130,853,000
Effect of dilutive employee stock awards (in shares)	2,146,000	2,577,000	2,196,000
Effect of dilutive convertible notes (in shares)	0	0	1,422,000
Effect of dilutive warrants (in shares)	0	0	1,024,000
Denominator for diluted earnings per share - weighted-average shares outstanding (in shares)	126,259,000	126,152,000	135,495,000
Basic (in dollars per share)	$ 2.48	$ 4.08	$ 5.21
Diluted (in dollars per share)	$ 2.44	$ 4.00	5.03
Anti-dilutive stock-based awards excluded from calculations	1,800,000
Senior Notes Due 2019
Denominator:
Strike price of warrants (in dollars per share)			$ 94.42