Uncompleted Contracts (Tables)

3 Months Ended

Mar. 31, 2020

Costs, estimated earnings and billings on uncompleted contracts are as follows:

	March 31,			December 31,
	2020			2019
Revenue recognized	$	1,405,800		$	1,074,800
Less: billings to date		(920,200	)		(832,300	)
Costs and estimated earnings in excess of billings on uncompleted contracts		485,600			242,500

Billings to date		878,600			2,707,200
Revenue recognized		(415,500	)		(2,380,100	)
Revenue contract liabilities	$	463,100		$	327,100