Long-Term Debt (Detail Textuals) (USD $)			3 Months Ended
Mar. 31, 2013 Line of credit	Dec. 31, 2012 Line of credit	Mar. 31, 2013 Industrial Development Revenue Bonds; secured by an equivalent letter of credit from a bank with interest payable monthly at a floating rate (0.37% at December 31, 2012)(A)
Debt Instrument [Line Items]
Annual sinking fund payments commenced December 1, 2000 through 2013			$ 170,000
Percentage of annual fee of secured amount			1.00%
Percentage of annual fee of principal amount outstanding			0.25%
Final sinking fund payment due December 1, 2014			2,620,000
Unsecured line of credit	$ 2,000,000	$ 2,000,000

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 129

-Paragraph 2, 4

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19(b),22(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant