CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Common Stock.	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Common Class A [Member]	Total
Balance at Dec. 31, 2020	$ 7	$ 1,047,052	$ 2,342,329		$ 3,389,388
Balance (in shares) at Dec. 31, 2020	70,906
Changes in stockholders' equity
Net income			581,097		581,097
Stock based compensation		14,622			14,622
Stock based compensation (in shares)	803
Issuance of common stock in settlement of directors' fees		101			101
Issuance of common stock in settlement of directors' fees (in shares)	2
Common stock dividends			(27,940)		(27,940)
Repurchase of common stock	$ (1)	(443,438)		$ (443,439)	(443,439)
Repurchase of common stock (in shares)	(7,227)			(7,227)
Balance at Jun. 30, 2021	$ 6	618,337	2,895,486		3,513,829
Balance (in shares) at Jun. 30, 2021	64,484
Balance at Mar. 31, 2021	$ 7	762,585	2,704,822		3,467,414
Balance (in shares) at Mar. 31, 2021	66,961
Changes in stockholders' equity
Net income			204,229		204,229
Stock based compensation		10,621			10,621
Stock based compensation (in shares)	96
Issuance of common stock in settlement of directors' fees		50			50
Issuance of common stock in settlement of directors' fees (in shares)	1
Common stock dividends			(13,565)		(13,565)
Repurchase of common stock	$ (1)	(154,919)		$ (154,920)	(154,920)
Repurchase of common stock (in shares)	(2,574)			(2,574)
Balance at Jun. 30, 2021	$ 6	618,337	2,895,486		3,513,829
Balance (in shares) at Jun. 30, 2021	64,484
Balance at Dec. 31, 2021	$ 6	125,396	3,292,923		3,418,325
Balance (in shares) at Dec. 31, 2021	56,867
Changes in stockholders' equity
Net income			302,756		302,756
Stock based compensation		17,823			17,823
Stock based compensation (in shares)	817
Issuance of common stock in settlement of directors' fees		102			102
Issuance of common stock in settlement of directors' fees (in shares)	2
Common stock dividends			(22,564)		(22,564)
Repurchase of common stock	$ (1)	(143,321)	(111,735)	$ (255,057)	(255,057)
Repurchase of common stock (in shares)	(4,747)			(4,747)
Balance at Jun. 30, 2022	$ 5		3,461,380		3,461,385
Balance (in shares) at Jun. 30, 2022	52,939
Balance at Mar. 31, 2022	$ 6		3,441,597		3,441,603
Balance (in shares) at Mar. 31, 2022	55,342
Changes in stockholders' equity
Net income			129,163		129,163
Stock based compensation		15,352			15,352
Stock based compensation (in shares)	23
Issuance of common stock in settlement of directors' fees		51			51
Issuance of common stock in settlement of directors' fees (in shares)	1
Common stock dividends			(11,139)		(11,139)
Repurchase of common stock	$ (1)	$ (15,403)	(98,241)	$ (113,645)	(113,645)
Repurchase of common stock (in shares)	(2,427)			(2,427)
Balance at Jun. 30, 2022	$ 5		$ 3,461,380		$ 3,461,385
Balance (in shares) at Jun. 30, 2022	52,939