Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Gains (Losses) [Member]	Treasury Stock [Member]
Beginning Balance at Dec. 31, 2018	$ 3,584,653	$ 1,444	$ 2,018,143	$ 1,769,415	$ 21	$ (204,370)
Beginning Balance, shares at Dec. 31, 2018		144,383,662				6,945,309
Net loss	(73,328)			(73,328)
Stock-based compensation, net of tax	570	$ 2	1,412			$ (844)
Stock-based compensation, net of tax, shares		223,330				81,480
Net loss on investments	(18)				(18)
Net loss on derivative financial instruments	(1)				(1)
Ending Balance at Mar. 31, 2019	3,511,876	$ 1,446	2,019,555	1,696,087	2	$ (205,214)
Ending Balance, shares at Mar. 31, 2019		144,606,992				7,026,789
Beginning Balance at Dec. 31, 2019	3,232,210	$ 1,448	2,024,347	1,412,201	(18)	$ (205,768)
Beginning Balance, shares at Dec. 31, 2019		144,781,766				7,077,856
Net loss	(861,940)			(861,940)
Stock-based compensation, net of tax	1,219	$ 3	1,540			$ (324)
Stock-based compensation, net of tax, shares		325,280				85,131
Net loss on derivative financial instruments	(1)				(1)
Ending Balance at Mar. 31, 2020	$ 2,371,488	$ 1,451	$ 2,025,887	$ 550,261	$ (19)	$ (206,092)
Ending Balance, shares at Mar. 31, 2020		145,107,046				7,162,987