Condensed Consolidated Statements of Changes in Common Stockholders' Equity Statement - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Treasury Stock [Member]	Noncontrolling Interest [Member]
As of at Dec. 31, 2020	$ 3,766,393	$ 20,000	$ 388,159	$ 6,804,822	$ 603,314	$ (4,056,993)	$ 7,091
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income for the period	112,635			112,635
Net income attributable to noncontrolling interest	0			(185)			185
Change in redemption value of redeemable noncontrolling interest	761		697				64
Distribution to noncontrolling interest	(126)						(126)
Dividends on common stock	(15,106)			(15,106)
Issuance of Class B common stock, net of restricted stock award forfeitures	(104)		(5,188)			5,084
Amortization of unearned stock compensation and stock option expense	1,589		1,589
Other comprehensive loss, net of income taxes	(1,203)				(1,203)
Purchase of redeemable noncontrolling interest	0
As of at Mar. 31, 2021	3,864,839	20,000	385,257	6,902,166	602,111	(4,051,909)	7,214
As of at Dec. 31, 2020	11,928
Increase (Decrease) in Temporary Equity [Roll Forward]
Change in redemption value of redeemable noncontrolling interests	(634)
Purchase of redeemable noncontrolling interest	(3,508)
As of at Mar. 31, 2021	7,786
As of at Dec. 31, 2021	4,411,669	20,000	389,456	7,126,761	971,388	(4,108,022)	12,086
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income for the period	96,566			96,566
Net income attributable to noncontrolling interest	0			(986)			986
Net loss attributable to redeemable noncontrolling interests	44			44
Change in redemption value of redeemable noncontrolling interest	64						64
Distribution to noncontrolling interest	(357)						(357)
Dividends on common stock	(15,497)			(15,497)
Repurchase of Class B Common Stock	(9,527)					(9,527)
Issuance of Class B common stock, net of restricted stock award forfeitures	1,437					1,437
Amortization of unearned stock compensation and stock option expense	1,677		1,677
Other comprehensive loss, net of income taxes	(13,135)				(13,135)
As of at Mar. 31, 2022	4,472,941	$ 20,000	$ 391,133	$ 7,206,888	$ 958,253	$ (4,116,112)	$ 12,779
As of at Dec. 31, 2021	14,311
Increase (Decrease) in Temporary Equity [Roll Forward]
Net income (loss) attributable to redeemable noncontrolling interests	(44)
Change in redemption value of redeemable noncontrolling interests	64
As of at Mar. 31, 2022	$ 14,331