Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2024	Jun. 30, 2023
Earnings Per Share [Abstract]
Net Income	$ 192,439	$ 78,885	$ 232,250	$ 101,699	$ 271,324	$ 333,949
Participating Securities, Distributed and Undistributed Earnings (Loss), Basic	1,018		1,219		1,417	1,779
Net Income (Loss) Available to Common Stockholders, Basic	$ 191,421		$ 231,031		$ 269,907	$ 332,170
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Anti-dilutive stock options excluded from diluted earnings per share computations (in shares)	56		64		57	65
Incremental Common Shares Attributable to Participating Nonvested Shares with Non-forfeitable Dividend Rights	208,000		205,000		206,000	209,000
Weighted average shares outstanding: [Abstract]
Basic (in shares)	38,124		38,837		38,164	38,857
Effect of dilutive securities: [Abstract]
Stock options and employee stock purchase plan (in shares)	201		278		235	298
Diluted (in shares)	38,325		39,115		38,399	39,155
Earnings Per Share, Basic [Abstract]
Basic (in dollars per share)	$ 5.02		$ 5.95		$ 7.07	$ 8.55
Earnings Per Share, Basic and Diluted [Abstract]
Diluted (in dollars per share)	$ 4.99		$ 5.91		$ 7.03	$ 8.48