Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023
Earnings Per Share [Abstract]
Net Income	$ 125,701	$ 192,439	$ 78,885	$ 137,843	$ 232,250	$ 101,699	$ 397,025	$ 471,792
Participating Securities, Distributed and Undistributed Earnings (Loss), Basic	654			726			2,071	2,504
Net Income (Loss) Available to Common Stockholders, Basic	$ 125,047			$ 137,117			$ 394,954	$ 469,288
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)	88			31			57	64
Incremental Common Shares Attributable to Participating Nonvested Shares with Non-forfeitable Dividend Rights	206,000			205,000			206,000	207,000
Weighted average shares outstanding: [Abstract]
Basic (in shares)	37,983			38,735			38,104	38,816
Effect of dilutive securities: [Abstract]
Stock options and employee stock purchase plan (in shares)	204			288			226	296
Diluted (in shares)	38,187			39,023			38,330	39,112
Earnings Per Share, Basic [Abstract]
Basic (in dollars per share)	$ 3.29			$ 3.54			$ 10.37	$ 12.09
Earnings Per Share, Basic and Diluted [Abstract]
Diluted (in dollars per share)	$ 3.27			$ 3.51			$ 10.30	$ 12.00