Condensed Consolidated Statements of Stockholders' Equity Statement - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]
Total Stockholders' Equity at Dec. 31, 2018	$ 4,020,331	$ 3	$ 394,342	$ (49,129)	$ 3,722,073	$ (46,958)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss) Attributable to Parent	865,195				865,195
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(34,007)					(34,007)
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	8,505		8,505
Treasury Stock Reissued at Lower than Repurchase Price	3,831			5,398	(1,567)
Total Stockholders' Equity at Mar. 31, 2019	4,863,855	3	402,847	(43,731)	4,585,701	(80,965)
Total Stockholders' Equity at Dec. 31, 2018	4,020,331	3	394,342	(49,129)	3,722,073	(46,958)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss) Attributable to Parent	1,205,189
Proceeds from Issuance of Common Stock	9,740
Total Stockholders' Equity at Sep. 30, 2019	5,131,192	3	396,432	(30,443)	4,917,313	(152,113)
Total Stockholders' Equity at Mar. 31, 2019	4,863,855	3	402,847	(43,731)	4,585,701	(80,965)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss) Attributable to Parent	598,810				598,810
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	31,392					31,392
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	7,818		7,818
Proceeds from Issuance of Common Stock	(64)		(64)
Treasury Stock, Value, Acquired, Cost Method	(15,001)			(15,001)
Total Stockholders' Equity at Jun. 30, 2019	5,486,810	3	410,601	(58,732)	5,184,511	(49,573)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss) Attributable to Parent	(258,816)				(258,816)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(102,540)					(102,540)
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	9,029		9,029
Proceeds from Issuance of Common Stock	1,708		1,708
Treasury Stock Reissued at Lower than Repurchase Price	0		(24,906)	33,288	(8,382)
Treasury Stock, Value, Acquired, Cost Method	(4,999)			(4,999)
Total Stockholders' Equity at Sep. 30, 2019	5,131,192	3	396,432	(30,443)	4,917,313	(152,113)
Total Stockholders' Equity at Dec. 31, 2019	5,755,057	3	410,020	(38,397)	5,470,779	(87,348)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss) Attributable to Parent	685,912				685,912
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(61,607)					(61,607)
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	9,654		9,654
Proceeds from Issuance of Common Stock	4,068		4,068
Treasury Stock, Value, Acquired, Cost Method	(100,005)			(100,005)
Total Stockholders' Equity at Mar. 31, 2020	6,293,079	3	423,742	(138,402)	6,156,691	(148,955)
Total Stockholders' Equity at Dec. 31, 2019	5,755,057	3	410,020	(38,397)	5,470,779	(87,348)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss) Attributable to Parent	2,967,165
Proceeds from Issuance of Common Stock	15,181
Total Stockholders' Equity at Sep. 30, 2020	8,825,145	3	412,313	(100,067)	8,428,925	83,971
Total Stockholders' Equity at Mar. 31, 2020	6,293,079	3	423,742	(138,402)	6,156,691	(148,955)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss) Attributable to Parent	966,429				966,429
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	87,813					87,813
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	8,878		8,878
Proceeds from Issuance of Common Stock	(2,797)		(2,797)
Treasury Stock Reissued at Lower than Repurchase Price	0		(338)	365	(27)
Total Stockholders' Equity at Jun. 30, 2020	7,353,402	3	429,485	(138,037)	7,123,093	(61,142)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss) Attributable to Parent	1,314,824				1,314,824
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	145,113					145,113
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	10,732		10,732
Proceeds from Issuance of Common Stock	1,080		1,080
Treasury Stock Reissued at Lower than Repurchase Price	(6)		(28,984)	37,970	(8,992)
Total Stockholders' Equity at Sep. 30, 2020	$ 8,825,145	$ 3	$ 412,313	$ (100,067)	$ 8,428,925	$ 83,971