Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net Income	$ 2,079,082	$ 2,356,980
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	1,231,546	1,242,357
(Gain) Loss on the sale of equipment	(1,700)	29,658
Deferred income taxes	(291,000)	134,000
Changes in operating assets and liabilities:
Accounts receivable, net	(3,131)	114,813
Inventories, net	9,593	519
Other current assets	38,034	177,001
Accounts payable	29,620	(64,644)
Accrued wages and salaries	(16,210)	79,042
Other accrued expenses	(109,042)	138,512
Unearned revenue and customer deposits	26,642	(181,056)
Net cash provided by operating activities	2,993,434	4,027,182
Cash flows from investing activities:
Capital expenditures	(1,333,988)	(2,027,860)
Proceeds from the sale of equipment	1,700	3,730
Proceeds from certificates of deposit	7,063,000	6,225,000
Purchases of certificates of deposit	(6,814,000)	(7,719,000)
Net cash used in investing activities	(1,083,288)	(3,518,130)
Cash flows from financing activities:
Cash dividends paid	(1,111,052)	(956,471)
Net cash used in financing activities	(1,111,052)	(956,471)
Net increase (decrease) in cash and cash equivalents	799,094	(447,419)
Cash and cash equivalents at beginning of year	353,475	800,894
Cash and cash equivalents at end of year	1,152,569	353,475
Net cash paid for income taxes	706,000	840,000
Supplemental schedule of non-cash investing activities:
Capital expenditures in accounts payable	$ 3,953	$ 0