Changes in Equity - Changes in Equity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	$ 1,043,196	$ 772,887
Net income	114,417	86,568
Issuance of common stock related to stock split	0
Share-based compensation, net of forfeitures	3,416	2,370
Repurchases of common stock and related excise taxes	(10,445)	(6,749)
Shares exchanged for tax withholdings	(1,207)	(939)
Periodic pension costs, net of income taxes	(21)	(25)
Ending balance	$ 1,122,449	$ 829,051
Cash dividends per share of common stock (in dollars per share)	$ 1.17	$ 1.08
Periodic pension costs, net of income taxes	$ 6	$ 6
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance (in shares)	23,007,681	23,087,037
Beginning balance	$ 78	$ 78
Issuance of common stock related to stock split	$ 153
Share-based compensation, net of forfeitures (in shares)	8,373	5,268
Repurchases of common stock and related excise taxes (in shares)	(20,106)	(10,881)
Shares exchanged for tax withholdings (in shares)	(2,469)	(1,464)
Ending balance (in shares)	22,993,479	23,079,960
Ending balance	$ 231	$ 78
Treasury Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(144,998)	(104,139)
Share-based compensation, net of forfeitures	4,698	3,033
Repurchases of common stock and related excise taxes	(10,445)	(6,749)
Shares exchanged for tax withholdings	(1,207)	(939)
Ending balance	(151,952)	(108,794)
Additional Paid-in Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	14,613	8,293
Issuance of common stock related to stock split	(153)
Share-based compensation, net of forfeitures	(1,297)	(560)
Ending balance	13,163	7,733
Accum. Other Comp. Income (Loss)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	1,831	2,516
Periodic pension costs, net of income taxes	(21)	(25)
Ending balance	1,810	2,491
Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	1,171,672	866,139
Net income	114,417	86,568
Share-based compensation, net of forfeitures	15	(103)
Ending balance	1,259,197	927,543
Dividend Paid
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends paid	$ (26,907)	$ (25,061)
Cash dividends per share of common stock (in dollars per share)	$ 1.17	$ 1.08
Dividend Paid | Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends paid	$ (26,907)	$ (25,061)