Note 7 - Supplemental Financial Statement Information (Details) (USD $)	3 Months Ended	9 Months Ended
Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Supplemental Cash Flow Elements [Abstract]
Income Taxes Paid			$ 1,905,474	$ 1,524,245
Payments of Dividends			2,160,326	1,930,504
Common Stock, Dividends, Per Share, Cash Paid (in Dollars per share)			$ 0.47	$ 0.42
Research and Development Expense	$ 259,535	$ 246,119	$ 558,458	$ 536,509

- Definition

The aggregate costs incurred (1) in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or (2) to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, including the costs of developing computer software up to the point in time of achieving technological feasibility, and costs allocated in accounting for a business combination to in-process projects deemed to have no alternative future use.

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