Consolidated Statements of Shareholders' Equity (Unaudited) - USD ($) shares in Thousands	Common Stock [Member] Common Class A [Member]	Common Stock [Member] Common Class B [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock, Common [Member]	Retained Earnings [Member] Common Class A [Member]	Retained Earnings [Member] Common Class B [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Parent [Member] Common Class A [Member]	Parent [Member] Common Class B [Member]	Parent [Member]	Noncontrolling Interest [Member]	Common Class A [Member]	Common Class B [Member]	Total
Balance (in shares) at Dec. 31, 2022	63,518	18,125
Balance at Dec. 31, 2022			$ 572,000	$ 500,642,000	$ (130,930,000)			$ 1,378,337,000	$ (4,130,000)			$ 1,744,491,000	$ 18,531,000			$ 1,763,022,000
Stock options exercised and stock awards (in shares)	228
Stock options exercised and stock awards			2,000	3,412,000								3,414,000				3,414,000
Stock-based compensation related to stock options, restricted shares and employee stock purchase plan				13,080,000								13,080,000
Vesting of restricted share awards (in shares)		422
Vesting of restricted share awards			3,000	(6,964,000)								(6,961,000)				(6,961,000)
Issuance of common stock under employee stock purchase plan (in shares)	102
Issuance of common stock under employee stock purchase plan				2,828,000								2,828,000				2,828,000
Common stock repurchases (in shares)	(623)	(84)
Common stock repurchases					(25,280,000)							(25,280,000)				(25,280,000)
Cash dividends declared						$ (8,897,000)	$ (2,692,000)			$ (8,897,000)	$ (2,692,000)
Foreign currency translation adjustment									232,000			232,000
Net income								90,455,000				90,455,000	335,000
Balance (in shares) at Mar. 31, 2023	63,225	18,463
Balance at Mar. 31, 2023			577,000	512,998,000	(156,210,000)			1,457,203,000	(3,898,000)			1,810,670,000	18,866,000			1,829,536,000
Balance (in shares) at Dec. 31, 2022	63,518	18,125
Balance at Dec. 31, 2022			572,000	500,642,000	(130,930,000)			1,378,337,000	(4,130,000)			1,744,491,000	18,531,000			1,763,022,000
Foreign currency translation adjustment																(187,000)
Net income																269,948,000
Balance (in shares) at Sep. 30, 2023	62,053	17,989
Balance at Sep. 30, 2023			804,000	533,648,000	(16,169,000)			1,385,646,000	(4,317,000)			1,899,612,000	19,471,000			1,919,083,000
Balance (in shares) at Mar. 31, 2023	63,225	18,463
Balance at Mar. 31, 2023			577,000	512,998,000	(156,210,000)			1,457,203,000	(3,898,000)			1,810,670,000	18,866,000			1,829,536,000
Stock options exercised and stock awards (in shares)	237
Stock options exercised and stock awards			1,000	3,479,000								3,480,000				3,480,000
Stock-based compensation related to stock options, restricted shares and employee stock purchase plan				5,952,000								5,952,000				5,952,000
Vesting of restricted share awards				(54,000)								(54,000)				(54,000)
Common stock repurchases (in shares)	(890)	(195)
Common stock repurchases					(40,305,000)							(40,305,000)				(40,305,000)
Cash dividends declared						(8,812,000)	(2,725,000)			(8,812,000)	(2,725,000)			$ (8,812,000)	$ (2,725,000)
Foreign currency translation adjustment									1,689,000			1,689,000				1,689,000
Net income								98,275,000				98,275,000	249,000			98,524,000
Balance (in shares) at Jun. 30, 2023	62,572	18,268
Balance at Jun. 30, 2023			578,000	522,375,000	(196,515,000)			1,543,941,000	(2,209,000)			1,868,170,000	19,115,000			1,887,285,000
Stock options exercised and stock awards (in shares)	124
Stock options exercised and stock awards			1,000	1,888,000								1,889,000				1,889,000
Stock-based compensation related to stock options, restricted shares and employee stock purchase plan				6,265,000								6,265,000				6,265,000
Issuance of common stock under employee stock purchase plan (in shares)	107
Issuance of common stock under employee stock purchase plan			1,000	3,123,000								3,124,000				3,124,000
Common stock repurchases (in shares)	(750)	(279)
Common stock repurchases					(44,174,000)							(44,174,000)				(44,174,000)
Cash dividends declared						(10,574,000)	(3,255,000)			(10,574,000)	(3,255,000)			(10,574,000)	(3,255,000)
Foreign currency translation adjustment									(2,108,000)			(2,108,000)				(2,108,000)
Net income								80,278,000				80,278,000	356,000			80,634,000
Balance (in shares) at Sep. 30, 2023	62,053	17,989
Balance at Sep. 30, 2023			804,000	533,648,000	(16,169,000)			1,385,646,000	(4,317,000)			1,899,612,000	19,471,000			1,919,083,000
Retirement of treasury shares and par value adjustment			224,000	(3,000)	224,520,000			(224,744,000)				(3,000)				(3,000)
Balance (in shares) at Dec. 31, 2023	61,461	16,364
Balance at Dec. 31, 2023			806,000	542,046,000	(119,835,000)			1,450,025,000	(2,163,000)			1,870,879,000				1,890,416,000
Stock options exercised and stock awards (in shares)	383
Stock options exercised and stock awards			4,000	5,997,000								6,001,000				6,001,000
Stock-based compensation related to stock options, restricted shares and employee stock purchase plan												14,090,000
Vesting of restricted share awards (in shares)		351
Vesting of restricted share awards			4,000	(9,486,000)								(9,482,000)				(9,482,000)
Issuance of common stock under employee stock purchase plan (in shares)	97
Issuance of common stock under employee stock purchase plan			1,000	3,354,000								3,355,000				3,355
Common stock repurchases (in shares)	(128)
Common stock repurchases					(5,627,000)							(5,627,000)				(5,627,000)
Cash dividends declared						(10,467,000)	(2,964,000)			(10,467,000)	(2,964,000)
Foreign currency translation adjustment									(1,891,000)			(1,891,000)
Net income								71,608,000				71,608,000	(119,000)			71,489,000
Balance (in shares) at Mar. 31, 2024	61,813	16,715
Balance at Mar. 31, 2024			815,000	556,001,000	(125,462,000)			1,508,202,000	(4,054,000)			1,935,502,000	19,418,000			1,954,920,000
Balance (in shares) at Dec. 31, 2023	61,461	16,364
Balance at Dec. 31, 2023			806,000	542,046,000	(119,835,000)			1,450,025,000	(2,163,000)			1,870,879,000				1,890,416,000
Foreign currency translation adjustment																(1,806,000)
Net income																229,692,000
Balance (in shares) at Sep. 30, 2024	62,308	16,695
Balance at Sep. 30, 2024			820,000	577,665,000	(129,644,000)			1,638,257,000	(3,969,000)			2,083,129,000	19,828,000			2,102,957,000
Balance (in shares) at Mar. 31, 2024	61,813	16,715
Balance at Mar. 31, 2024			815,000	556,001,000	(125,462,000)			1,508,202,000	(4,054,000)			1,935,502,000	19,418,000			1,954,920,000
Stock options exercised and stock awards (in shares)	134
Stock options exercised and stock awards			1,000	2,098,000								2,099,000				2,099,000
Stock-based compensation related to stock options, restricted shares and employee stock purchase plan				5,515,000								5,515,000				5,515,000
Vesting of restricted share awards				(10,000)								(10,000)				(10,000)
Common stock repurchases (in shares)	(78)	(15)
Common stock repurchases					(3,953,000)							(3,953,000)				(3,953,000)
Cash dividends declared						(10,523,000)	(3,024,000)			(10,523,000)	(3,024,000)			(10,523,000)	(3,024,000)
Foreign currency translation adjustment									(873,000)			(873,000)				(873,000)
Net income								78,661,000				78,661,000	122,000			78,783,000
Balance (in shares) at Jun. 30, 2024	61,869	16,700
Balance at Jun. 30, 2024			816,000	563,604,000	(129,415,000)			1,573,316,000	(4,927,000)			2,003,394,000	19,540,000			2,022,934,000
Stock options exercised and stock awards (in shares)	341
Stock options exercised and stock awards			3,000	5,257,000								5,260,000				5,260,000
Stock-based compensation related to stock options, restricted shares and employee stock purchase plan				5,293,000								5,293,000				5,293,000
Issuance of common stock under employee stock purchase plan (in shares)	99
Issuance of common stock under employee stock purchase plan			1,000	3,511,000								3,512,000				3,512,000
Common stock repurchases (in shares)	(1)	(5)
Common stock repurchases					(229,000)							(229,000)				(229,000)
Cash dividends declared						$ (11,185,000)	$ (3,006,000)			$ (11,185,000)	$ (3,006,000)			$ (11,185,000)	$ (3,006,000)
Foreign currency translation adjustment									958,000			958,000				958,000
Net income								79,132,000				79,132,000	288,000			79,420,000
Balance (in shares) at Sep. 30, 2024	62,308	16,695
Balance at Sep. 30, 2024			$ 820,000	$ 577,665,000	$ (129,644,000)			$ 1,638,257,000	$ (3,969,000)			$ 2,083,129,000	$ 19,828,000			$ 2,102,957,000