Operating Segments - Condensed Consolidated Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Segment Reporting Information [Line Items]
Revenue	$ 138,772	$ 133,746
Gross profit	18,224	19,623
Selling, general and administrative expenses	16,799	16,045
Amortization of intangibles	143	175
Operating income	1,282	3,403
Interest expense, net	(2,158)	(833)
Gain on sale of property and equipment	29	12
Gain on change in fair value of warrant liability	161	0
Total unallocated amounts	(1,968)	(821)
Income (loss) before income taxes	(686)	2,582
Depreciation and amortization	1,504	1,413
Construction
Segment Reporting Information [Line Items]
Revenue		104,459
Service
Segment Reporting Information [Line Items]
Revenue		29,287
Operating Segments \| Construction
Segment Reporting Information [Line Items]
Revenue	109,486	104,459
Gross profit	10,982	12,915
Selling, general and administrative expenses	10,174	10,452
Depreciation and amortization	1,030	973
Operating Segments \| Service
Segment Reporting Information [Line Items]
Revenue	29,286	29,287
Gross profit	7,242	6,708
Selling, general and administrative expenses	6,330	5,226
Depreciation and amortization	331	265
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Selling, general and administrative expenses	295	367
Depreciation and amortization	$ 143	$ 175

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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