Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Cash flows from operating activities
Net income (loss)	$ 4,751	$ (9,557)
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Depreciation and amortization	12,311	13,108
Amortization of ROU operating leases	3,066	2,927
Amortization of ROU finance leases	1,585	1,154
Unamortized debt issuance costs upon debt modification		399
Amortization of deferred debt issuance costs	286	186
Deferred income taxes	(99)	43
Stock-based compensation	1,629	1,728
Gain on sale of property and equipment	(1,361)	(746)
Allowance for credit losses	411
Change in operating assets and liabilities:
Accounts receivable	23,645	(28,257)
Income tax receivable	(97)	(398)
Inventory	(172)	252
Prepaid expenses and other	900	126
Costs and estimated earnings in excess of billings on uncompleted contracts	5,050	(14,424)
Accounts payable	(23,680)	6,261
Accrued liabilities	2,818	(1,601)
Operating lease liabilities	(2,721)	(2,896)
Income tax payable	(296)	409
Billings in excess of costs and estimated earnings on uncompleted contracts	5,048	30,204
Net cash provided by (used in) operating activities	33,074	(1,082)
Cash flows from investing activities:
Proceeds from sale of property and equipment	1,749	847
Purchase of property and equipment	(5,036)	(8,118)
Contributions to CSV life insurance	(99)	(444)
Insurance claim proceeds related to property and equipment	1,342	2,574
Net cash used in investing activities	(2,044)	(5,141)
Cash flows from financing activities:
Borrowings from Credit Facility	5,000	32,000
Payments made on borrowings from Credit Facility	(24,500)	(29,500)
Loan costs from Credit Facility	(391)	(825)
Payments of finance lease liabilities	(1,858)	(1,412)
Purchase of vested stock-based awards	(24)
Exercise of stock options		35
Net cash (used in) provided by financing activities	(21,773)	298
Net change in cash and cash equivalents	9,257	(5,925)
Cash and cash equivalents at beginning of period	1,086	8,684
Cash and cash equivalents at end of period	10,343	2,759
Supplemental disclosures of cash flow information, cash paid during the period for:
Interest	2,130	3,926
Taxes, net of refunds	$ 1,663	$ 394