Consolidated Balance Sheets (Parenthetical) - USD ($) |
Dec. 31, 2017 |
Dec. 31, 2016 |
|---|---|---|
| Current assets | ||
| Accounts receivable, allowance for doubtful accounts | $ 35,000 | $ 82,000 |
| Liabilities and Shareholders' Equity | ||
| Common stock, par value (in dollars per share) | $ 1 | $ 1 |
| Common stock, shares authorized (in shares) | 24,000,000 | 24,000,000 |
| Common stock, shares issued (in shares) | 10,300,000 | 10,300,000 |
| Common stock in treasury, at cost (in shares) | 1,566,769 | 1,630,690 |
| Unamortized Debt Issuance Expense | $ 257,787 | $ 117,950 |
| X | ||||||||||
- Definition A valuation allowance for trade and other receivables due to an Entity within one year (or the normal operating cycle, whichever is longer) that are expected to be uncollectible. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Face amount or stated value per share of common stock. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The maximum number of common shares permitted to be issued by an entity's charter and bylaws. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Number of common and preferred shares that were previously issued and that were repurchased by the issuing entity and held in treasury on the financial statement date. This stock has no voting rights and receives no dividends. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|