Condensed Consolidated Statements Of Income (Loss) And Retained Earnings (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Income Statement [Abstract]
NET SALES	$ 44,970,920	$ 38,167,606	$ 111,764,454	$ 95,057,325
COST OF SALES	32,797,657	32,378,577	88,609,931	82,401,911
Gross profit from operations	12,173,263	5,789,029	23,154,523	12,655,414
SELLING, GENERAL AND ADMINISTRATIVE EXPENSES	4,131,984	3,730,580	11,636,439	10,965,657
Income from operations	8,041,279	2,058,449	11,518,084	1,689,757
OTHER INCOME (EXPENSE):
Interest income	13,720	48,999	75,379	108,719
Interest expense	(71,843)	(91,525)	(197,772)	(230,220)
Gain on sale of equity investments	0	0	0	3,881,872
Dividend income	422,650	87,786	622,496	1,573,786
Other, net	194,083	20,498	457,668	(12,628)
Total other income (expense)	558,610	65,758	957,771	5,321,529
Income from continuing operations before income taxes	8,599,889	2,124,207	12,475,855	7,011,286
PROVISION FOR INCOME TAXES	2,405,000	702,000	3,490,000	1,963,000
Equity in affiliate income (loss), net of tax	52,489	(3,022)	58,327	(15,275)
Net income from continuing operations	6,247,378	1,419,185	9,044,182	5,033,011
Discontinued operations:
Loss from operations of Tulsa Dynaspan, Inc. and Beaver Lake Concrete, Inc. (including gain on disposal of assets of $0, $0, $0, and $0, respectively)	0	616,180	(177,306)	(4,359,989)
PROVISION FOR (BENEFIT FROM) INCOME TAXES	0	66,000	(50,000)	(1,218,000)
Net income (loss) from discontinued operations	0	550,180	(127,306)	(3,141,989)
NET INCOME	6,247,378	1,969,365	8,916,876	1,891,022
RETAINED EARNINGS, beginning of period	100,247,941	96,413,662	98,518,546	97,758,013
Dividends, Common Stock, Cash	913,211	919,544	1,824,501	1,842,680
Stock Repurchased and Retired During Period, Value	45,916	387,416	74,729	730,288
RETAINED EARNINGS, end of period	$ 105,536,192	$ 97,076,067	$ 105,536,192	$ 97,076,067
Basic earnings (loss) per share:
From continuing operations	$ 1.57	$ 0.36	$ 2.28	$ 1.26
From discontinued operations	$ 0.00	$ 0.14	$ (0.03)	$ (0.78)
Net earnings per share	$ 1.57	$ 0.50	$ 2.25	$ 0.48
Common Stock, Dividends, Per Share, Declared	$ 0.23	$ 0.23	$ 0.46	$ 0.46