Consolidated Statements of Changes in Stockholders' Equity - 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, 2016		402,334,655			3,906,877
Beginning balance at Dec. 31, 2016	$ 468,448	$ 402	$ 2,534,670	$ (2,018,989)	$ (47,635)
Issued or purchased pursuant to stock compensation plans, shares		5,201,854
Issued or purchased pursuant to stock compensation plans, value		$ 6	(6)
Issued pursuant to directors' compensation plan, shares		12,837
Issued pursuant to notes conversion, value	0
Stock-based compensation, value	19,721		19,721
Tax withholding - stock compensation, shares					1,550,164
Tax withholding - stock compensation, value	(3,183)				$ (3,183)
Retirement of treasury stock, shares		(5,000,000)			(5,000,000)
Retirement of treasury stock, value		$ (5)	(46,557)		$ 46,562
Dividends adjustments, value	27			27
Net income	163,152			163,152
Ending balance, shares at Dec. 31, 2017		402,549,346			457,041
Ending balance at Dec. 31, 2017	648,165	$ 403	2,507,828	(1,855,810)	$ (4,256)
Issued or purchased pursuant to stock compensation plans, shares		4,556,424
Issued or purchased pursuant to stock compensation plans, value		$ 4	(4)
Issued pursuant to notes conversion, shares		55,249,955
Issued pursuant to notes conversion, value	162,004	$ 55	161,949
Stock-based compensation, value	15,438		15,438
Tax withholding - stock compensation, shares					1,484,708
Tax withholding - stock compensation, value	(6,528)				$ (6,528)
Retirement of treasury stock, value					$ 0
Net income	$ 322,698			322,698
Ending balance, shares at Dec. 31, 2018	462,355,725	462,355,725			1,941,749
Ending 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		9,315,016
Issued or purchased pursuant to stock compensation plans, value		$ 9	(9)
Issued pursuant to directors' compensation plan, shares	97,537
Issued pursuant to senior subordinated notes exchanges, shares		36,297,217			(1,990,000)
Issued pursuant to senior subordinated notes exchanges, value	$ 39,555	$ 37	37,409	(5,161)	$ 7,270
Issued pursuant to notes conversion, value	0
Stock-based compensation, value	16,488		16,488
Tax withholding - stock compensation, shares					1,701,022
Tax withholding - stock compensation, value	(2,520)				$ (2,520)
Retirement of treasury stock, value					$ 0
Net income	$ 216,959			216,959
Ending balance, shares at Dec. 31, 2019	508,065,495	508,065,495			1,652,771
Ending balance at Dec. 31, 2019	$ 1,412,259	$ 508	$ 2,739,099	$ (1,321,314)	$ (6,034)