Computation of Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2025	Mar. 31, 2025	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2025	Jun. 30, 2024
Numerator:
Net income used for calculating basic and diluted income per share	$ 240,783	$ 210,939	$ 229,548	$ 210,545	$ 451,722	$ 440,093
Denominator:
Weighted average number of common shares used in the calculation of basic income per share (in shares)	77,157		77,816		77,257	78,078
Dilutive effect of outstanding awards associated with stock-based compensation plans (in shares)	202		472		349	573
Shares used in the calculation of diluted income per share (in shares)	77,359		78,288		77,606	78,651
Basic income per share (in dollars per share)	$ 3.12		$ 2.95		$ 5.85	$ 5.64
Diluted income per share (in dollars per share)	$ 3.11		$ 2.93		$ 5.82	$ 5.60
Antidilutive securities excluded from computation of (loss) income per share (in shares)	400		100		300	100