Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash flows from operating activities
Net (loss) income	$ (3,620)	$ (8,060)	$ 6,877
Adjustments to reconcile net loss to net cash provided by operating activities
Depreciation and amortization	34,162	28,083	23,451
Deferred financing cost amortization	1,225	462	0
Bad debt expense	0	22	993
Deferred income taxes	751	(2,885)	1,869
Stock-based compensation	2,280	2,275	1,594
(Gain) loss on sale of property and equipment	(1,579)	466	(359)
Change in operating assets and liabilities, net of effects of acquisitions:
Accounts receivable	(23,935)	(2,666)	(4,202)
Income tax receivable	(49)	249	0
Inventory	1,696	1,150	(3,702)
Accounts receivable, non-current	(511)	(222)	0
Prepaid expenses and other	856	(467)	(695)
Costs and estimated earnings in excess of billings on uncompleted contracts	19,640	(10,655)	(19,725)
Accounts payable	(5,717)	12,245	(1,178)
Accrued liabilities	(1,123)	1,658	4,428
Income tax payable	(125)	(1,097)	538
Billings in excess of costs and estimated earnings on uncompleted contracts	(802)	4,655	2,109
Deferred revenue	0	(34)	(53)
Net cash provided by operating activities	23,149	25,179	11,945
Cash flows from investing activities:
Proceeds from sale of property and equipment	2,152	2,708	1,005
Purchase of property and equipment	(18,715)	(20,802)	(18,711)
Net cash used in investing activities	(17,686)	(128,795)	(42,787)
Cash flows from financing activities:
Borrowings from Credit Facility	57,000	149,021	30,000
Payments made on borrowings from Credit Facility	(63,084)	(42,955)	(1,557)
Extinguishment of debt	0	(32,427)	0
Loan costs from Credit Facility	(486)	(4,498)	0
Exercise of stock options	67	28	869
Purchase of shares into treasury	0	(3,101)	(436)
Net cash (used in) provided by financing activities	(6,503)	66,068	28,876
Net change in cash and cash equivalents	(1,040)	(37,548)	(1,966)
Cash and cash equivalents at beginning of year	1,345	38,893	40,859
Cash and cash equivalents at end of year	305	1,345	38,893
Supplemental disclosures of cash flow information, cash paid during the period for:
Interest	5,031	3,063	742
Taxes, net of refunds	999	584	770
Acquisition of TAS and purchase price adjustment
Cash flows from investing activities:
Payments for acquisition of businesses	(369)	(110,344)	0
Houston Industrial Tool Services, Inc.
Cash flows from investing activities:
Payments for acquisition of businesses	0	(357)	0
Acquisition of business in Pacific Northwest
Cash flows from investing activities:
Payments for acquisition of businesses	0	0	(25,081)
Acquisition of TW LaQuay Dredging [Member]
Cash flows from investing activities:
Payments for acquisition of businesses	$ (754)	$ 0	$ 0