Computation of 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
Numerator:
Net income used for calculating basic and diluted income per share	$ 229,548	$ 210,545	$ 198,043	$ 295,783	$ 440,093	$ 493,826
Denominator:
Weighted average number of common shares used in the calculation of basic income per share (in shares)	77,816		79,285		78,078	79,368
Dilutive effect of outstanding awards associated with stock-based compensation plans (in shares)	472		535		573	647
Shares used in the calculation of diluted income per share (in shares)	78,288		79,820		78,651	80,015
Basic income per share (in dollars per share)	$ 2.95		$ 2.50		$ 5.64	$ 6.22
Diluted income per share (in dollars per share)	$ 2.93		$ 2.48		$ 5.60	$ 6.17
Antidilutive securities excluded from computation of (loss) income per share (in shares)	100		200		100	200