Statements of Cash Flows (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Cash flows from operating activities:
Net income	$ 4,830,780	$ 4,716,530
Depreciation and amortization	254,441	255,583
Net loss (gain) on sale of assets	14,861	(18,251)
Realized loss on sales of marketable securities	22,931	8,765
Increase (reduction) in allowance for bad debts	11,054	(5,092)
Deferred income taxes	59,541	40,999
Increase (decrease) in cash resulting from changes in operating assets and liabilities:
Accounts receivable	624,758	(557,636)
Receivable from damage settlement	(518,050)
Inventories	224,684	(146,045)
Prepaid expenses and other current and non-current assets	30,576	89,168
Prepaid income taxes	75,011
Accounts payable	(249,004)	192,145
Accrued expenses and taxes payable	(836)	(139,037)
Net cash provided by operating activities	5,380,747	4,437,129
Cash flows from investing activities:
Acquisitions of plant and equipment	(252,356)	(274,645)
Proceeds from the sale of assets	30,350	38,658
Purchases of marketable securities	(4,266,419)	(3,987,606)
Proceeds from sales of marketable securities	6,016,244	3,040,000
Net cash provided by (used in) investing activities	1,527,819	(1,183,593)
Cash flows from financing activities:
Dividends paid	(6,251,158)	(3,677,151)
Net cash used in financing activities	(6,251,158)	(3,677,151)
Net increase (decrease) in cash and cash equivalents	657,408	(423,615)
Cash and cash equivalents, beginning of year	1,090,974	1,514,589
Cash and cash equivalents, end of year	$ 1,748,382	$ 1,090,974