Current and Long-Term Financing (Debt Schedule) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Current portion of borrowings outstanding	$ 2,112	$ 795
Long-term portion of borrowings outstanding	24,353	17,148
NACoal
Debt Instrument [Line Items]
Revolving credit agreement	30,000	16,000
Other debt	16,465	8,943
Total debt outstanding	46,465	24,943
Current portion of borrowings outstanding	22,112	7,795
Long-term portion of borrowings outstanding	24,353	17,148
Total available borrowings, net of limitations, under revolving credit agreement	146,951	148,644
Unused revolving credit agreement	$ 116,951	$ 132,644
Weighted average stated interest rate on total borrowings	2.30%	5.10%

Amount of short-term and long-term debt and lease obligation.

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The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

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Amount of long-term debt and lease obligation, classified as noncurrent.

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Amount of long-term debt and lease obligation, classified as current.

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