Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash flows from operating activities:
Net income (loss)	$ (7,990)	$ (35,412)	$ 45,546
Loss from discontinued operations	0	3,847	6,461
Income (loss) from continuing operations	(7,990)	(31,565)	52,007
Adjustments to reconcile to net cash provided by operating activities:
Depreciation and amortization	43,791	44,312	40,329
Gain on sale of fixed assets	(929)	(310)	(816)
Equity-based compensation expense	7,987	5,073	5,647
Deferred income taxes	924	(16,816)	(2,675)
Equity in earnings of affiliated companies	0	(570)	(5,159)
Non-cash restructuring charges	1,816	20,592	0
Fixed asset impairment	0	11,870	0
Definite-lived intangible asset impairment	0	12,116	0
Goodwill impairment	43,484	51,512	0
Debt issuance costs	3,377	157	1,964
Earnout reversal	0	0	(4,175)
(Gain) loss on sale of businesses	3,414	988	(11,771)
Loss on foreign currency transactions	80	627	2,425
Other	(168)	1,279	1,588
Changes in operating assets and liabilities (net of acquisitions):
Restricted cash related to operating activities	(382)	(454)	(102)
Return on equity of affiliated companies	0	590	10,691
Receivables net, retainage and costs and estimated earnings in excess of billings	12,283	(41,211)	8,222
Inventories	6,984	(5,286)	(736)
Prepaid expenses and other assets	(28,895)	3,465	(9,685)
Accounts payable and accrued expenses	(582)	5,997	8,944
Billings in excess of costs and estimated earnings	45,700	19,100	(6,340)
Other operating	1,129	402	(2,293)
Net cash provided by operating activities of continuing operations	132,023	81,868	88,065
Net cash used in operating activities of discontinued operations	0	(1,045)	(3,761)
Net cash provided by operating activities	132,023	80,823	84,304
Cash flows from investing activities:
Capital expenditures	(29,454)	(32,899)	(26,085)
Proceeds from sale of fixed assets	3,173	1,547	3,435
Patent expenditures	(1,503)	(1,923)	(2,032)
Restricted cash related to investing activities	(3,538)	(1,153)	0
Purchase of Schultz Mechanical Contractors, Inc.	(6,662)	0	0
Purchase of Fyfe Asia, net of cash acquired	(1,098)	0	0
Purchase of Brinderson, net of cash acquired	0	1,000	(143,763)
Proceeds from sale of interests in Bayou Coating, L.L.C.	0	9,065	0
Proceeds from sale of Ka-te Insituform AG	0	1,123	0
Proceeds from sale of interests in German joint venture	0	0	18,300
Net cash used in investing activities of continuing operations	(39,082)	(23,240)	(150,145)
Net cash provided by investing activities of discontinued operations	0	1,045	845
Net cash used in investing activities	(39,082)	(22,195)	(149,300)
Cash flows from financing activities:
Proceeds from issuance of common stock upon stock option exercises, including tax effects	2,466	8,615	594
Repurchase of common stock	(27,804)	(31,085)	(27,648)
Sale of non-controlling interest	239	0	0
Purchase of or distributions to non-controlling interests	(472)	(617)	(287)
Payment of earnout related to acquisition of CRTS, Inc.	(684)	0	(2,112)
Credit facility financing fees	(4,360)	(783)	(5,013)
Proceeds from notes payable	1,505	1,284	1,541
Principal payments on notes payable	(1,875)	0	(183)
Proceeds from line of credit	26,000	18,000	0
Payments on line of credit	(71,500)	(8,000)	0
Proceeds from long-term debt	350,000	0	385,500
Principal payments on long-term debt	(323,750)	(22,039)	(253,500)
Net cash provided by (used in) financing activities	(50,235)	(34,625)	98,892
Effect of exchange rate changes on cash	(5,975)	(7,083)	(9,527)
Net increase in cash and cash equivalents for the year	36,731	16,920	24,369
Cash and cash equivalents, beginning of year	174,965	158,045	133,676
Cash and cash equivalents, end of year	211,696	174,965	158,045
Cash and cash equivalents associated with assets held for sale, end of year	(2,443)	0	0
Cash and cash equivalents from continuing operations, end of year	209,253	174,965	158,045
Supplemental disclosures of cash flow information:
Interest	9,873	9,602	8,700
Income taxes	$ 8,753	$ 12,594	$ 11,630