Operating Segments - Condensed Consolidated Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information [Line Items]
Revenue	$ 135,185	$ 132,603	$ 273,957	$ 266,350
Gross profit	20,335	17,695	38,559	37,319
Selling, general and administrative expenses	13,752	17,079	30,552	33,124
Amortization of intangibles	274	175	417	350
Operating income	6,309	441	7,590	3,845
Interest expense, net	(2,137)	(1,597)	(4,295)	(2,430)
Gain (loss) on sale of property and equipment	(13)	9	17	21
Loss on debt extinguishment	0	(513)	0	(513)
Gain (loss) on change in fair value of warrant liability	(102)	(103)	59	(103)
Total unallocated amounts	(2,252)	(2,204)	(4,219)	(3,025)
Income (loss) before income taxes	4,057	(1,763)	3,371	820
Depreciation and amortization	1,636	1,460	3,140	2,873
Construction
Segment Reporting Information [Line Items]
Revenue		104,759		209,219
Service
Segment Reporting Information [Line Items]
Revenue		27,844		57,131
Operating Segments | Construction
Segment Reporting Information [Line Items]
Revenue	105,937	104,759	215,423	209,219
Gross profit	12,213	10,683	23,195	23,599
Selling, general and administrative expenses	8,024	11,229	18,200	21,681
Depreciation and amortization	1,032	1,003	2,062	1,976
Operating Segments | Service
Segment Reporting Information [Line Items]
Revenue	29,248	27,844	58,534	57,131
Gross profit	8,122	7,012	15,364	13,720
Selling, general and administrative expenses	5,588	5,335	11,917	10,561
Depreciation and amortization	330	282	661	547
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Selling, general and administrative expenses	140	515	435	882
Depreciation and amortization	$ 274	$ 175	$ 417	$ 350