Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Cash flows from operating activities:
Net income	$ 27,670	$ 61,880	$ 27,325
Loss from discontinued operations		100	4,070
Income from continuing operations	27,670	61,980	31,395
Adjustments to reconcile to net cash provided by operating activities:
Depreciation and amortization	36,039	30,732	28,440
Equity-based compensation expense	6,491	6,713	4,839
Deferred income taxes	(2,320)	8,024	3,994
Equity in earnings of affiliated companies	(3,471)	(7,291)	(1,192)
Earnout reversal	(1,700)	(1,700)	(1,600)
(Gain) loss on foreign currency transactions	(1,155)	98	(85)
Other	200	(1,173)	(1,345)
Changes in operating assets and liabilities:
Restricted cash	663	538	567
Return on equity method investments	7,018	7,803	2,537
Receivables net, retainage and costs and estimated earnings in excess of billings	(38,310)	(39,214)	(19,363)
Inventories	(5,992)	(9,677)	954
Prepaid expenses and other assets	2,045	(539)	8,991
Accounts payable and accrued expenses	(2,248)	(3,781)	491
Other operating	(2,046)	962	(327)
Net cash provided by operating activities of continuing operations	22,884	53,475	58,296
Net cash provided by (used in) operating activities of discontinued operations		(446)	6,162
Net cash provided by operating activities	22,884	53,029	64,458
Cash flows from investing activities:
Capital expenditures	(21,554)	(36,858)	(21,837)
Proceeds from sale of fixed assets	755	482	1,855
Patent expenditures	(1,130)	(1,346)	(2,705)
Purchase of Garneau, Inc. assets and remaining interests in joint ventures			(11,624)
Purchase of Singapore licensee		(1,257)
Proceeds from net foreign investment hedges			6,818
Net cash used in investing activities of continuing operations	(166,063)	(38,979)	(237,207)
Net cash provided by investing activities of discontinued operations			798
Net cash used in investing activities	(166,063)	(38,979)	(236,409)
Cash flows from financing activities:
Stock repurchase program	(5,000)
Distributions/dividends to noncontrolling interests	(1,661)	(398)	(959)
Investments by noncontrolling interests	546	2,578	4,107
Purchase of noncontrolling interests in Insituform Linings			(3,979)
Proceeds from notes payable	354	1,986	2,637
Principal payments on notes payable	(1,499)	(1,808)	(4,159)
Credit facility and other financing fees	(4,320)
Principal payments on long-term debt	(103,750)	(10,000)	(7,500)
Proceeds from long-term debt	250,000		53,700
Net cash provided by (used in) financing activities	142,280	(5,340)	172,845
Effect of exchange rate changes on cash	(7,801)	55	5,849
Net increase (decrease) in cash and cash equivalents for the period	(8,700)	8,765	6,743
Cash and cash equivalents, beginning of year	114,829	106,064	99,321
Cash and cash equivalents, end of year	106,129	114,829	106,064
Cash paid for:
Interest	17,231	7,046	8,173
Net income taxes paid	10,077	19,001	7,143
CRTS, Hockway and Fyfe NA [Member]
Cash flows from investing activities:
Purchase of businesses, net of cash acquired	(144,134)
Bayou and Corrpro [Member]
Cash flows from investing activities:
Purchase of businesses, net of cash acquired			(209,714)
All Other Issuances [Member]
Cash flows from financing activities:
Proceeds from issuance of common stock	3,610	2,302	128,998
Issued In Connection With Acquisition [Member]
Cash flows from financing activities:
Proceeds from issuance of common stock	$ 4,000