Income Taxes (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Current
Federal	$ 3,863,151	$ 6,157,900
State	558,993	1,014,213
Current Total	4,422,144	7,172,113
Deferred
Federal	(3,270,928)	570,770
State	(115,219)	66,885
Deferred Total	(3,386,147)	637,655
Total	1,035,997	7,809,768
Income tax provision	1,035,997	7,809,768
Discontinued operations	(164,235)	(66,077)
Total	871,762	7,743,691
Deferred tax assets
Accrued vacation	113,893	146,215
Acquisition costs capitalized	58,886	98,484
Accrued remediation costs	130,168	80,100
Accrued payables	174,674	122,235
Percentage completed contract method for tax	276,413	0
Accrued workers’ compensation	159,237	127,033
Capitalized bidding costs	121,227	8,846
Inventory adjustments	139,565	133,991
Accrued lease expense	17,902	32,683
Accrued contract losses	50,220	89
Other	4,103	5,214
Total deferred tax assets	1,246,288	754,890
Deferred tax liabilities
Tax amortization in excess of financial statement amortization	(10,850)	(12,156)
Tax depreciation in excess of financial statement depreciation	(5,934,158)	(8,947,058)
Total deferred tax liabilities	(5,945,008)	(8,959,214)
Total net deferred tax liabilities	(4,698,720)	(8,204,324)
Non-current deferred tax liability	4,698,720	$ 8,204,324
One-time income tax benefit	2,500,000
Capital expenditures qualifying for immediate expensing	140,000
Minimum amount of future taxable income required to realize deferred tax assets	$ 5,000,000
Schedule of differences between effective income tax rate and federal statutory rate
Federal statutory rate	34.00%	35.00%
State tax rate, net of federal tax	3.10%	3.30%
Nondeductible expenses	3.60%	1.60%
Domestic production activities deduction	(4.00%)	(3.20%)
Tax Act rate change	(26.00%)	0.00%
Other	0.10%	0.60%
Total	10.80%	37.30%
Reconciliation of beginning and ending unrecognized tax benefits
Balance as of January 1	$ 4,723	$ 4,723
Increase from current year tax positions	0	0
Decrease from settlements with taxing authority	0	0
Balance as of December 31	5,000	4,723
Income tax interest and penalties expensed during period	1,000	1,000
Accrued income tax interest and penalties	$ 9,000	$ 8,000