Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Cash flows from operating activities:
Net income	$ (239)	$ 1,931	$ 6,431	$ 9,310
Adjustment to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	2,576	2,633	7,224	8,153
Unrealized foreign currency loss			302	496
Net gain on interest rate swaps				(248)
Loss on sale of property and equipment			104	58
Loss on divestitures, net of selling costs				70
Debt discount amortization			311	928
Share-based compensation expense			1,237	2,684
Bad debt expense	100	300	625	710
Inventory reserve expense			453	454
Deferred income tax benefit			13	(595)
Changes in operating assets and liabilities, net of acquisitions and divestitures:
Accounts receivable			12,705	(6,090)
Costs and estimated earnings in excess of billings on uncompleted contracts			(5,714)	(5,196)
Inventories			2,568	527
Prepaid expense and other current assets			(1,713)	(3,853)
Deferred charges and other assets			(2,858)	(1,628)
Accounts payable and accrued expenses			443	(4,217)
Billings in excess of costs and estimated earnings on uncompleted contracts			(13,504)	2,879
Income taxes payable			21	(1,679)
Other liabilities			467	(3,396)
Net cash provided by (used in) operating activities			9,115	(633)
Cash flows from investing activities:
Acquisitions of property and equipment			(2,875)	(3,746)
Net cash paid for acquisition			(5,895)
Proceeds from sale of property and equipment			605	509
Net cash used in by investing activities			(8,165)	(3,237)
Cash flows from financing activities:
Borrowings on revolving credit lines			87,000	38,300
Repayments on revolving credit lines			(74,500)	(44,447)
Repayments of long-term debt			(4,384)	(2,325)
Deferred financing fees paid				(1,117)
Payments on finance leases and financing liability			(333)	(368)
Proceeds from employee stock purchase plan and exercise of stock options				76
Net cash provided by (used in) financing activities			7,783	(9,881)
Effect of exchange rate changes on cash, cash equivalents and restricted cash			657	(448)
Net increase (decrease) in cash, cash equivalents and restricted cash			9,390	(14,199)
Cash, cash equivalents and restricted cash at beginning of period			36,958	44,438	$ 44,438
Cash, cash equivalents and restricted cash at end of period	$ 46,348	$ 30,239	46,348	30,239	$ 36,958
Cash paid (received) during the period for:
Interest			2,450	2,651
Income taxes			$ (112)	$ 5,234