Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Reconciliation of information used in computing basic and diluted earnings per share [Abstract]
Net earnings	$ 242,239	$ 289,618	$ 470,813	$ 515,771
Basic earnings per common share:
Net earnings (in dollars per share)	$ 1.73	$ 2.01	$ 3.37	$ 3.58
Weighted average shares outstanding (in shares)	139,862	143,832	139,810	143,959
Diluted earnings per common share:
Net earnings (in dollars per share)	$ 1.72	$ 2.00	$ 3.35	$ 3.56
Weighted average shares outstanding (in shares)	140,578	144,669	140,597	144,998
Reconciliation Of Share Amounts Used In Computing Earnings Per Share [Abstract]
Weighted average shares outstanding - basic (in shares)	139,862	143,832	139,810	143,959
Dilutive effect of assumed exercise of SARs and vesting of performance shares and RSUs (in shares)	716	837	787	1,039
Weighted average shares outstanding - diluted (in shares)	140,578	144,669	140,597	144,998
Antidilutive securities excluded from computation of earnings per share	34	6	61	32