Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Common Class A [Member] Common Stock [Member]	Common Class A [Member] Retained Earnings [Member]	Common Class A [Member] Parent [Member]	Common Class A [Member]	Common Class B [Member] Common Stock [Member]	Common Class B [Member] Retained Earnings [Member]	Common Class B [Member] Parent [Member]	Common Class B [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock, Common [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Parent [Member]	Noncontrolling Interest [Member]	Total
Balance (in shares) at Dec. 31, 2021	64,662,000				18,598,000
Balance at Dec. 31, 2021									$ 563	$ 470,750	$ (36,933)	$ 1,031,582	$ 787	$ 1,466,749		$ 1,466,749
Stock options exercised and stock awards (in shares)	585,000
Stock options exercised and stock awards									4	8,029				8,033		8,033
Stock-based compensation related to stock options, restricted shares and employee stock purchase plan										25,315				25,315		25,315
Vesting of restricted share awards					$ 457				3	(8,669)				(8,666)		(8,666)
Issuance of common stock under employee stock purchase plan (in shares)	201,000
Issuance of common stock under employee stock purchase plan									2	5,217				5,219		5,219
Common stock repurchases (in shares)	(1,930,000)				(930,000)
Common stock repurchases											(93,997)			(93,997)		(93,997)
Cash dividends declared on common stock		$ (34,207)	$ (34,207)	$ (34,207)		$ (10,420)	$ (10,420)	$ (10,420)
Reclassification of foreign currency translation related to equity method													(601)	(601)		(601)
Foreign currency translation adjustment													(4,316)	(4,316)		(4,316)
Noncontrolling interest equity															$ 17,828	17,828
Net income												391,382		391,382	703	392,085
Balance (in shares) at Dec. 31, 2022	63,518,000				18,125,000
Balance at Dec. 31, 2022									572	500,642	(130,930)	1,378,337	(4,130)	1,744,491	18,531	1,763,022
Stock options exercised and stock awards (in shares)	822
Stock options exercised and stock awards									6	12,120				12,126		12,126
Stock-based compensation related to stock options, restricted shares and employee stock purchase plan										30,354				30,354		30,354
Vesting of restricted share awards									3	(7,018)				(7,015)		(7,015)
Issuance of common stock under employee stock purchase plan (in shares)	209,000
Issuance of common stock under employee stock purchase plan									1	5,951				5,952		5,952
Common stock repurchases (in shares)	(3,088,000)				(2,182,000)
Common stock repurchases											(213,425)			(213,425)		(213,425)
Cash dividends declared on common stock		(38,727)	(38,727)	(38,727)		(11,896)	(11,896)	(11,896)
Foreign currency translation adjustment													1,967	1,967		1,967
Net income												347,055		347,055	1,006	348,061
Vesting of restricted share awards (in shares)					421
Retirement of treasury shares and par value adjustment									224	(3)	224,520	(224,744)		(3)		(3)
Balance (in shares) at Dec. 31, 2023	61,461,000				16,364,000
Balance at Dec. 31, 2023									806	542,046	(119,835)	1,450,025	(2,163)	1,870,879	19,537	$ 1,890,416
Stock options exercised and stock awards (in shares)	1,243															1,225,271
Stock options exercised and stock awards									12	18,494				18,506		$ 18,506
Stock-based compensation related to stock options, restricted shares and employee stock purchase plan										30,350				30,350		30,350
Vesting of restricted share awards									4	(10,116)				(10,112)		(10,112)
Issuance of common stock under employee stock purchase plan (in shares)	196,000
Issuance of common stock under employee stock purchase plan									2	6,865				6,867		6,867
Common stock repurchases (in shares)	(295)				(52)
Common stock repurchases											(16,400)			(16,400)		(16,400)
Cash dividends declared on common stock		$ (43,449)	$ (43,449)	$ (43,449)		$ (12,115)	$ (12,115)	$ (12,115)
Foreign currency translation adjustment													(7,130)	(7,130)		(7,130)
Net income												304,153		304,153	817	304,970
Vesting of restricted share awards (in shares)					351,000
Balance (in shares) at Dec. 31, 2024	62,605,000				16,663,000
Balance at Dec. 31, 2024									$ 824	$ 587,639	$ (136,235)	$ 1,698,614	$ (9,293)	$ 2,141,549	$ 20,354	$ 2,161,903