Stockholders' Equity - Reclassifications From Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Tax effect	$ 0
Prior service credit
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before tax	(2)	$ (2)
Actuarial loss
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before tax	101	94
Defined Benefit Pension and Postretirement Items
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before tax	99	92
Tax effect	0	0
Amounts reclassified from accumulated other comprehensive loss, net of tax	$ 99	$ 92