Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
SEC Schedule, 12-09, Allowance, Credit Loss [Member]
Balance at Beginning of Period		$ 450	$ 747	$ 1,869
Additions - Charged to Costs and Expenses	[1]	0	6	458
Additions - Charged to Other Accounts	[2]	0	0	(1,422)
Deductions	[3]	138	303	158
Balance at End of Period		312	450	$ 747
SEC Schedule, 12-09, Valuation Allowance, Deferred Tax Asset [Member]
Balance at Beginning of Period		0
Additions - Charged to Costs and Expenses	[1]	520
Additions - Charged to Other Accounts	[2]	0
Deductions	[3]	0
Balance at End of Period		$ 520	$ 0

[1] Amounts charged to selling and general expenses for allowance for doubtful accounts and provision for income taxes from continuing operations for valuation allowance for deferred tax assets.

[2] Amounts charged to other accounts. Charged to the loss on divestiture of AMTEC Less Lethal Systems, Inc. (see Note Q to the Consolidated Financial Statements.

[3] Principally bad debts written off, net of recoveries.