Restatement and Revision of Prior Period Quarterly Financial Statements - Condensed Consolidated Statements of Cash Flows (Unaudited) (Details) - USD ($) $ in Thousands	3 Months Ended								6 Months Ended		9 Months Ended		12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2017	Jun. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accounting Changes and Error Corrections [Abstract]
Net income (loss)	$ (738)	$ 7,116	$ 4,374	$ 5,678	$ 4,765	$ 4,225	$ (1,905)	$ (3,136)	$ 10,052	$ (5,043)	$ 17,168	$ (817)	$ 16,430	$ 3,949	$ (32,389)
Depreciation, Depletion and Amortization				2,904				4,596	6,086	9,316	9,403	14,382	13,390	17,916	17,472
Share-based Compensation				1,419				1,241	2,921	2,358	5,296	4,097	6,820	5,572	5,873
Deferred income taxes				478				(546)	624	557	448	372	4,072	4,226	5,879
Change in fair value of contingent consideration liability		(167)	1,884	(1,040)		788	7,276	1,911	844	9,187	677	9,975	677	10,417	(270)
Intangible asset impairment charges									0	789			0	70	202
Bad debt provision				175				656	82	0	268	1,433	454	2,171	1,685
Excess Tax Benefit from Share-based Compensation, Operating Activities													0	(4,030)	0
Other Operating Activities, Cash Flow Statement				52				52	104	105	157	156	210	210	210
Increase decrease in accounts receivable and unbilled receivables				(4,680)				(15,863)	(26,620)	(4,738)	(35,732)	(11,573)	(41,877)	(2,651)	(10,580)
Increase (Decrease) in Inventories				(226)				453	1,890	(725)	(17,726)	(10,027)	(4,245)	6,355	(9,676)
Increase (Decrease) in Prepaid Expense and Other Assets				(1,167)				5,968	(971)	5,742	(10,567)	(7,622)	(13,547)	(8,206)	(4,140)
Accounts payable				(8,396)				(31,526)	3,370	(21,506)	7,395	(31,551)	18,152	(38,408)	25,102
Accrued expenses and other liabilities				4,923				11,627	(69)	3,110	10,830	7,543	15,520	12,933	3,582
Net cash provided by operating activities				120				(24,566)	(1,687)	(848)	(12,383)	(23,632)	16,056	10,525	43,402
Payments to Acquire Property, Plant, and Equipment				(3,042)				(3,987)	(7,024)	(7,445)	(10,274)	(10,502)	(12,483)	(13,319)	(15,034)
Net Cash Provided by (Used in) Investing Activities				(3,042)				(3,987)	(7,024)	(7,445)	(10,274)	(10,502)	(12,483)	(13,319)	(15,034)
Proceeds from (Repayments of) Lines of Credit				6,519				19,358	11,491	12,553	42,258	34,722	(867)	8,739	(5,281)
Net short-term secured borrowings (repayments)				(801)				(1,803)	37	104	633	(820)	20,709	405	(799)
Repurchases of common stock				(4,342)				0	(10,041)	0	(10,041)	0	(10,885)	0	(4,897)
Payment Of Contingent Consideration				0				(525)	(2,089)	(4,144)	(15,345)	(11,008)	(15,345)	(11,374)	(8,010)
Proceeds from Stock Options Exercised				189				984	1,319	1,090	1,824	2,002	2,663	2,636	1,195
Excess Tax Benefit from Share-based Compensation, Financing Activities				(95)				382	(119)	(474)	(850)	(680)	0	4,030	0
Proceeds from (Payments for) Other Financing Activities				1,470				18,396	598	9,129	18,479	24,216	(1,156)	(866)	(594)
Effect of Exchange Rate on Cash and Cash Equivalents				448				331	726	15	936	(50)	948	(607)	(1,805)
Cash and Cash Equivalents, Period Increase (Decrease)				(1,004)				(9,826)	(7,387)	851	(3,242)	(9,968)	(362)	169	8,177
Cash and Cash Equivalents, at Carrying Value	$ 30,562	$ 27,682	$ 23,537	$ 29,920	$ 30,924	$ 20,787	$ 31,606	$ 20,929	$ 23,537	$ 31,606	$ 27,682	$ 20,787	$ 30,562	$ 30,924	$ 30,755	$ 22,578