Accounts and Retention Receivables (Detail) (USD $)	Jun. 30, 2014	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, cost	$ 5,789,694	$ 5,283,935
Retention receivable, cost	540,945	498,095
Accounts And Retention Receivable Gross	6,330,639	5,782,030
Less: allowance for doubtful accounts	(31,734)	(31,961)
Accounts and retention receivable, net	$ 6,298,905	$ 5,750,069