Condensed Consolidated Statements of Shareholders' Equity (Unaudited) - USD ($)	Total	Common Stock	Retained (Loss) Earnings	Treasury Stock
Beginning Balances at Dec. 31, 2018	$ (1,048,622,000)	$ 2,137,443,000	$ (3,186,016,000)	$ (49,000)
Beginning Balances, Shares at Dec. 31, 2018		197,383
Fair value of employee stock plan grants	1,127,000	$ 1,127,000
Initial adoption | ASC 842	92,818,000		92,818,000
Net income (loss)	40,674,000		40,674,000
Ending Balances at Mar. 31, 2019	(914,003,000)	$ 2,138,570,000	(3,052,524,000)	(49,000)
Ending Balances, Shares at Mar. 31, 2019		197,383
Beginning Balances at Dec. 31, 2019	(844,814,000)	$ 2,140,520,000	(2,985,285,000)	(49,000)
Beginning Balances, Shares at Dec. 31, 2019		197,888
Net share settlements	(8,000)	$ 1,422	(8,000)
Fair value of employee stock plan grants	1,231,000	1,231,000
Net income (loss)	(217,605,000)		(217,605,000)
Ending Balances at Mar. 31, 2020	$ (1,061,196,000)	$ 2,141,751,000	$ (3,202,898,000)	$ (49,000)
Ending Balances, Shares at Mar. 31, 2020		199,310