Condensed Consolidated Statements of Stockholders' Deficit - USD ($) $ in Thousands	Common Stock	Preferred Stock	Treasury Stock	Additional Paid in Capital.	Equity-Based Compensation	Foreign Currency Translation Adjustment	Unrealized Pension Actuarial Losses, net of tax	Accumulated Deficit	Total
Beginning balance at Dec. 31, 2018	$ 15	$ 1	$ (10,342)	$ 445,452	$ 41,731	$ (6,423)	$ (9,301)	$ (702,391)	$ (241,258)
Beginning balance (in shares) at Dec. 31, 2018	150,142,955	4,569,233	2,549,185
Increase (Decrease) in Stockholders' Equity (Deficit)
Net loss								(32,172)	(32,172)
Equity-based compensation					2,798				2,798
Foreign currency translation adjustment						3,392			3,392
Net realized pension actuarial gains, net of tax							(224)		(224)
Ending balance at Mar. 31, 2019	$ 15	$ 1	$ (10,342)	445,452	44,529	(3,031)	(9,525)	(734,563)	(267,464)
Ending balance (in shares) at Mar. 31, 2019	150,142,955	4,569,233	2,549,185
Beginning balance at Dec. 31, 2018	$ 15	$ 1	$ (10,342)	445,452	41,731	(6,423)	(9,301)	(702,391)	(241,258)
Beginning balance (in shares) at Dec. 31, 2018	150,142,955	4,569,233	2,549,185
Increase (Decrease) in Stockholders' Equity (Deficit)
Net loss									(73,743)
Foreign currency translation adjustment									1,104
Net realized pension actuarial gains, net of tax									32
Ending balance at Jun. 30, 2019	$ 15	$ 1	$ (10,949)	445,452	47,190	(5,319)	(9,269)	(776,134)	(309,013)
Ending balance (in shares) at Jun. 30, 2019	150,007,085	4,569,233	2,787,147
Beginning balance at Dec. 31, 2018	$ 15	$ 1	$ (10,342)	445,452	41,731	(6,423)	(9,301)	(702,391)	(241,258)
Beginning balance (in shares) at Dec. 31, 2018	150,142,955	4,569,233	2,549,185
Increase (Decrease) in Stockholders' Equity (Deficit)
Net loss									(509,100)
Ending balance at Dec. 31, 2019	$ 15	$ 1	$ (10,949)	445,452	49,336	(7,329)	(8,059)	(1,211,508)	(743,041)
Ending balance (in shares) at Dec. 31, 2019	150,851,689	4,294,233	2,787,147
Beginning balance at Mar. 31, 2019	$ 15	$ 1	$ (10,342)	445,452	44,529	(3,031)	(9,525)	(734,563)	(267,464)
Beginning balance (in shares) at Mar. 31, 2019	150,142,955	4,569,233	2,549,185
Increase (Decrease) in Stockholders' Equity (Deficit)
Net loss								(41,571)	(41,571)
Equity-based compensation					2,661				2,661
Foreign currency translation adjustment						(2,288)			(2,288)
Net realized pension actuarial gains, net of tax							256		256
RSU's vested (in shares)	102,092
Shares repurchased			$ (607)						(607)
Shares repurchased (in shares)	(237,962)		237,962
Ending balance at Jun. 30, 2019	$ 15	$ 1	$ (10,949)	445,452	47,190	(5,319)	(9,269)	(776,134)	(309,013)
Ending balance (in shares) at Jun. 30, 2019	150,007,085	4,569,233	2,787,147
Beginning balance at Dec. 31, 2019	$ 15	$ 1	$ (10,949)	445,452	49,336	(7,329)	(8,059)	(1,211,508)	(743,041)
Beginning balance (in shares) at Dec. 31, 2019	150,851,689	4,294,233	2,787,147
Increase (Decrease) in Stockholders' Equity (Deficit)
Net loss								(12,670)	(12,670)
Equity-based compensation					861				861
Foreign currency translation adjustment						920			920
Net realized pension actuarial gains, net of tax							504		504
Preferred shares converted to common shares (in shares)	1,227,714	(1,004,183)
Shares returned in connection with the Appraisal Action following repayment of Margin Loan (in shares)	(4,570,734)		4,570,734
Ending balance at Mar. 31, 2020	$ 15	$ 1	$ (10,949)	445,452	50,197	(6,409)	(7,555)	(1,224,178)	(753,426)
Ending balance (in shares) at Mar. 31, 2020	147,508,669	3,290,050	7,357,881
Beginning balance at Dec. 31, 2019	$ 15	$ 1	$ (10,949)	445,452	49,336	(7,329)	(8,059)	(1,211,508)	(743,041)
Beginning balance (in shares) at Dec. 31, 2019	150,851,689	4,294,233	2,787,147
Increase (Decrease) in Stockholders' Equity (Deficit)
Net loss									(61,360)
Foreign currency translation adjustment									942
Net realized pension actuarial gains, net of tax									$ 537
Shares returned in connection with the Appraisal Action following repayment of Margin Loan (in shares)									4,570,734
Shares repurchased (in shares)									(2,787,147)
Settlement gain on related party payable to Ex-Sigma 2									$ 1,287
Ending balance at Jun. 30, 2020	$ 15	$ 1	$ (10,949)	446,739	51,118	(6,387)	(7,522)	(1,272,869)	(799,854)
Ending balance (in shares) at Jun. 30, 2020	147,511,430	3,290,050	7,355,120
Beginning balance at Mar. 31, 2020	$ 15	$ 1	$ (10,949)	445,452	50,197	(6,409)	(7,555)	(1,224,178)	(753,426)
Beginning balance (in shares) at Mar. 31, 2020	147,508,669	3,290,050	7,357,881
Increase (Decrease) in Stockholders' Equity (Deficit)
Net loss								(48,691)	(48,691)
Equity-based compensation					921				921
Foreign currency translation adjustment						22			22
Net realized pension actuarial gains, net of tax							33		33
Settlement gain on related party payable to Ex-Sigma 2				1,287					1,287
Adjustment to number of shares withheld in lieu of tax obligation of RSU holders in the year 2018	2,761		(2,761)
Ending balance at Jun. 30, 2020	$ 15	$ 1	$ (10,949)	$ 446,739	$ 51,118	$ (6,387)	$ (7,522)	$ (1,272,869)	$ (799,854)
Ending balance (in shares) at Jun. 30, 2020	147,511,430	3,290,050	7,355,120