Condensed Consolidated Statement of Changes in Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock ($.001 Par Value)	Paid-In Capital in Excess of Par	Retained Earnings (Accumulated Deficit)	Treasury Stock (at cost)
Beginning balance, shares at Dec. 31, 2018		462,355,725			1,941,749
Beginning balance at Dec. 31, 2018	$ 1,141,777	$ 462	$ 2,685,211	$ (1,533,112)	$ (10,784)
Issued or purchased pursuant to stock compensation plans, shares		1,331,050
Issued or purchased pursuant to stock compensation plans, value	2	$ 2
Issued pursuant to directors' compensation plan, shares		41,487
Stock-based compensation, value	4,306		4,306
Tax withholding - stock compensation, shares					531,494
Tax withholding - stock compensation, value	(1,091)				$ (1,091)
Net income (loss)	(25,674)			(25,674)
Ending balance, shares at Mar. 31, 2019		463,728,262			2,473,243
Ending balance at Mar. 31, 2019	1,119,320	$ 464	2,689,517	(1,558,786)	$ (11,875)
Beginning balance, shares at Dec. 31, 2018		462,355,725			1,941,749
Beginning balance at Dec. 31, 2018	1,141,777	$ 462	2,685,211	(1,533,112)	$ (10,784)
Net income (loss)	121,018
Ending balance, shares at Jun. 30, 2019		464,166,479			2,474,904
Ending balance at Jun. 30, 2019	1,270,676	$ 464	2,694,184	(1,412,094)	$ (11,878)
Beginning balance, shares at Mar. 31, 2019		463,728,262			2,473,243
Beginning balance at Mar. 31, 2019	1,119,320	$ 464	2,689,517	(1,558,786)	$ (11,875)
Issued or purchased pursuant to stock compensation plans, shares		400,850
Issued pursuant to directors' compensation plan, shares		37,367
Stock-based compensation, value	4,667		4,667
Tax withholding - stock compensation, shares					1,661
Tax withholding - stock compensation, value	(3)				$ (3)
Net income (loss)	146,692			146,692
Ending balance, shares at Jun. 30, 2019		464,166,479			2,474,904
Ending balance at Jun. 30, 2019	$ 1,270,676	$ 464	2,694,184	(1,412,094)	$ (11,878)
Beginning balance, shares at Dec. 31, 2019	508,065,495	508,065,495			1,652,771
Beginning balance at Dec. 31, 2019	$ 1,412,259	$ 508	2,739,099	(1,321,314)	$ (6,034)
Issued or purchased pursuant to stock compensation plans, shares		312,516
Issued pursuant to directors' compensation plan, shares		37,367
Stock-based compensation, value	3,204		3,204
Tax withholding - stock compensation, shares					175,673
Tax withholding - stock compensation, value	(34)				$ (34)
Net income (loss)	74,016			74,016
Ending balance, shares at Mar. 31, 2020		508,415,378			1,828,444
Ending balance at Mar. 31, 2020	$ 1,489,445	$ 508	2,742,303	(1,247,298)	$ (6,068)
Beginning balance, shares at Dec. 31, 2019	508,065,495	508,065,495			1,652,771
Beginning balance at Dec. 31, 2019	$ 1,412,259	$ 508	2,739,099	(1,321,314)	$ (6,034)
Net income (loss)	$ (623,458)
Ending balance, shares at Jun. 30, 2020	509,553,960	509,553,960			1,828,444
Ending balance at Jun. 30, 2020	$ 804,419	$ 510	2,754,749	(1,944,772)	$ (6,068)
Beginning balance, shares at Mar. 31, 2020		508,415,378			1,828,444
Beginning balance at Mar. 31, 2020	1,489,445	$ 508	2,742,303	(1,247,298)	$ (6,068)
Canceled pursuant to stock compensation plans, shares		(6,218,868)
Canceled pursuant to stock compensation plans, value		$ (6)	6
Stock-based compensation, value	$ 987		987
Stock issued pursuant to notes conversion, shares	7,400,000	7,357,450
Issued pursuant to notes conversion, value	$ 11,461	$ 8	11,453
Net income (loss)	$ (697,474)			(697,474)
Ending balance, shares at Jun. 30, 2020	509,553,960	509,553,960			1,828,444
Ending balance at Jun. 30, 2020	$ 804,419	$ 510	$ 2,754,749	$ (1,944,772)	$ (6,068)