Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Tax credit carryforwards	$ 20,300	$ 21,400
Net operating loss carryforwards	134,200	144,100
Accrued liabilities and other reserves	100
Pension		3,400
Capital losses	33,100	26,900
Other, net	44,200	40,600
Total deferred tax assets	231,900	236,400
Valuation allowance	(231,900)	(236,400)
Net deferred tax assets
Unremitted earnings of foreign subsidiaries	200	(200)
Total deferred tax liabilities	200	(200)
Valuation allowance
Total deferred tax liabilities	(200)	(200)
Net deferred tax liabilities	$ (200)	$ (200)