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)	Accumulated Other Comprehensive Income (Loss)	Treasury Stock (at cost)
Beginning balance, shares at Dec. 31, 2012		406,163,194				30,601,262
Beginning balance at Dec. 31, 2012	$ 5,114,889	$ 406	$ 3,136,461	$ 2,434,835	$ (348)	$ (456,465)
Stock Repurchase Program, shares	16,469,000					16,468,648
Stock Repurchase Program, value	$ (277,768)					$ (277,768)
Issued or purchased pursuant to employee stock compensation plans, shares		3,038,767
Issued or purchased pursuant to employee stock compensation plans, value	5,489	$ 3	5,486
Issued pursuant to employee stock purchase plan, shares						(860,901)
Issued pursuant to employee stock purchase plan, value	15,104		1,844			$ 13,260
Issued pursuant to directors' compensation plan, shares		13,612
Issued pursuant to directors' compensation plan, value	344		344
Stock-based compensation	42,091		42,091
Income tax benefit from equity awards	488		488
Tax withholding - stock compensation, shares						501,887
Tax withholding - stock compensation, value	(8,900)					$ (8,900)
Derivative contracts, net	72				72
Retirement of treasury stock, value	0
Net income (loss)	409,597			409,597
Ending balance, shares at Dec. 31, 2013		409,215,573				46,710,896
Ending balance at Dec. 31, 2013	$ 5,301,406	$ 409	3,186,714	2,844,432	(276)	$ (729,873)
Stock Repurchase Program, shares	12,398,000					12,398,017
Stock Repurchase Program, value	$ (200,369)					$ (200,369)
Issued or purchased pursuant to employee stock compensation plans, shares		2,541,809
Issued or purchased pursuant to employee stock compensation plans, value	7,023	$ 3	7,020
Issued pursuant to employee stock purchase plan, shares						(1,247,156)
Issued pursuant to employee stock purchase plan, value	16,358		(3,272)			$ 19,630
Issued pursuant to directors' compensation plan, shares		22,529
Issued pursuant to directors' compensation plan, value	412		412
Stock-based compensation	39,532		39,532
Income tax benefit from equity awards	12		12
Tax withholding - stock compensation, shares						553,750
Tax withholding - stock compensation, value	(8,618)					$ (8,618)
Derivative contracts, net	67				67
Cash dividends declared	(87,458)			(87,458)
Retirement of treasury stock, value	0
Net income (loss)	$ 635,491			635,491
Ending balance, shares at Dec. 31, 2014	411,779,911	411,779,911				58,415,507
Ending balance at Dec. 31, 2014	$ 5,703,856	$ 412	3,230,418	3,392,465	(209)	$ (919,230)
Stock Repurchase Program, shares	4,425,000					4,424,702
Stock Repurchase Program, value	$ (11,759)					$ (11,759)
Issued or purchased pursuant to employee stock compensation plans, shares		3,900,127
Issued or purchased pursuant to employee stock compensation plans, value	567	$ 5	562
Issued pursuant to employee stock purchase plan, shares						(353,480)
Issued pursuant to employee stock purchase plan, value	2,667		(2,867)			$ 5,534
Issued pursuant to directors' compensation plan, shares		292,407
Issued pursuant to directors' compensation plan, value	398		398
Share correction (Note 6), shares		(1,430,819)
Share correction (Note 6), value	(22,078)	$ (2)	(22,076)
Stock-based compensation	39,285		39,285
Income tax shortfall from equity awards	(8,102)		(8,102)
Tax withholding - stock compensation, shares						637,582
Tax withholding - stock compensation, value	(4,712)					$ (4,712)
Derivative contracts, net	209				209
Cash dividends declared	(65,971)			(65,971)
Retirement of treasury stock, shares		(60,000,000)				(60,000,000)
Retirement of treasury stock, value	0	$ (60)	(884,069)			$ 884,129
Net income (loss)	$ (4,385,448)			(4,385,448)
Ending balance, shares at Dec. 31, 2015	354,541,626	354,541,626				3,124,311
Ending balance at Dec. 31, 2015	$ 1,248,912	$ 355	$ 2,353,549	$ (1,058,954)	$ 0	$ (46,038)