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, 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	50,283,896	4,294,233	929,049
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
Shares returned in connection with the Appraisal Action following repayment of Margin Loan (in shares)	(1,523,578)		1,523,578						1,523,578
Preferred shares converted to common stock		(1,004,183)
Preferred shares converted to common stock (in shares)	409,238
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	49,169,556	3,290,050	2,452,627
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	50,283,896	4,294,233	929,049
Increase (Decrease) in Stockholders' Equity (Deficit)
Net loss									(178,500)
Ending balance at Dec. 31, 2020	$ 15	$ 1	$ (10,949)	446,739	52,183	(7,419)	(17,064)	(1,390,038)	(926,532)
Ending balance (in shares) at Dec. 31, 2020	49,242,225	3,290,050	2,451,706
Increase (Decrease) in Stockholders' Equity (Deficit)
Net loss								(39,200)	(39,200)
Equity-based compensation					387				387
Foreign currency translation adjustment						100			100
Net realized pension actuarial gains, net of tax							(157)		(157)
Preferred shares converted to common stock		(510,681)
Preferred shares converted to common stock (in shares)	223,413
Payment for fractional shares on Reverse Stock Split				(14)					(14)
Payment for fractional shares on Reverse Stock Split (in shares)	(5,445)
Issuance of Common Stock	$ 1			25,079					$ 25,080
Issuance of Common Stock (in shares)	9,731,819
Shares repurchased (in shares)									(929,049)
Ending balance at Mar. 31, 2021	$ 16	$ 1	$ (10,949)	$ 471,804	$ 52,570	$ (7,319)	$ (17,221)	$ (1,429,238)	$ (940,336)
Ending balance (in shares) at Mar. 31, 2021	59,192,012	2,779,369	2,451,706