Note 4 - Contracts in Progress - Costs, Estimated Earnings, and Billings on Uncompleted Contracts (Details) - USD ($)	Mar. 31, 2017	Dec. 31, 2016
Costs incurred on contract in progress	$ 7,940,004	$ 4,678,192
Estimated earnings	9,450,692	10,733,826
Total	17,390,696	15,412,018
Billings to date	(20,299,851)	(18,077,839)
Cost in excess of billing, net	(2,909,155)	(2,665,821)
Included in accompanying balance sheets under the following captions:
Costs and estimated earnings in excess of billings on contracts in progress	1,743,666	2,596,518
Billings in excess of costs and estimated earnings on contracts in progress	(4,652,821)	(5,262,339)
Cost in excess of billing, net	$ (2,909,155)	$ (2,665,821)