Condensed Consolidated Statement of Shareholders' Equity - USD ($) $ in Thousands	Total	Common Shares [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Treasury Stock, Common
Shares Outstanding, Beginning Balance at Dec. 31, 2023		27,761,299
Stockholders' Equity, Beginning Balance at Dec. 31, 2023	$ 2,516,939	$ 301	$ 349,907	$ 2,301,348	$ (134,617)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	284,807			284,807
Stock options exercised, shares		187,550
Stock options exercised	7,549		(3,623)		11,172
Stock-based compensation expense	7,349		7,349
Repurchase of common shares, shares		(600,000)
Repurchase of common shares	(75,585)				(75,585)
Deferral of executive and director compensation	58		58
Deferred Compensation Arrangement with Individual, Shares Issued		55,059
Deferred Compensation Arrangement with Individual, Distribution Paid	0		(3,137)		3,137
Shares Outstanding, Ending Balance at Jun. 30, 2024		27,403,908
Stockholders' Equity, Ending Balance at Jun. 30, 2024	2,741,117	$ 301	350,554	2,586,155	(195,893)
Shares Outstanding, Beginning Balance at Mar. 31, 2024		27,751,658
Stockholders' Equity, Beginning Balance at Mar. 31, 2024	2,638,785	$ 301	348,039	2,439,409	(148,964)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	146,746			146,746
Stock options exercised, shares		52,250
Stock options exercised	2,054		(1,324)		3,378
Stock-based compensation expense	3,810		3,810
Repurchase of common shares, shares		(400,000)
Repurchase of common shares	(50,307)				(50,307)
Deferral of executive and director compensation	29		29
Shares Outstanding, Ending Balance at Jun. 30, 2024		27,403,908
Stockholders' Equity, Ending Balance at Jun. 30, 2024	2,741,117	$ 301	350,554	2,586,155	(195,893)
Shares Outstanding, Beginning Balance at Dec. 31, 2024		27,063,023
Stockholders' Equity, Beginning Balance at Dec. 31, 2024	2,939,677	$ 301	348,705	2,865,073	(274,402)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	232,480			232,480
Stock options exercised, shares		40,000
Stock options exercised	1,864		(1,791)		3,655
Stock-based compensation expense	8,116		8,116
Repurchase of common shares, shares		(882,000)
Repurchase of common shares	(100,199)				(100,199)
Deferral of executive and director compensation	198		198
Deferred Compensation Arrangement with Individual, Shares Issued		118,763
Deferred Compensation Arrangement with Individual, Distribution Paid	0		(10,692)		10,692
Shares Outstanding, Ending Balance at Jun. 30, 2025		26,339,786
Stockholders' Equity, Ending Balance at Jun. 30, 2025	3,082,136	$ 301	344,536	3,097,553	(360,254)
Shares Outstanding, Beginning Balance at Mar. 31, 2025		26,772,622
Stockholders' Equity, Beginning Balance at Mar. 31, 2025	3,006,334	$ 301	342,367	2,976,310	(312,644)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	121,243			121,243
Stock options exercised, shares		16,000
Stock options exercised	758		(738)		1,496
Stock-based compensation expense	$ 3,916		3,916
Repurchase of common shares, shares	500,000	(460,000)
Repurchase of common shares	$ (50,144)				(50,144)
Deferral of executive and director compensation	29		29
Deferred Compensation Arrangement with Individual, Shares Issued		11,164
Deferred Compensation Arrangement with Individual, Distribution Paid	0		(1,038)		1,038
Shares Outstanding, Ending Balance at Jun. 30, 2025		26,339,786
Stockholders' Equity, Ending Balance at Jun. 30, 2025	$ 3,082,136	$ 301	$ 344,536	$ 3,097,553	$ (360,254)