Restructuring (Details) $ in Thousands	1 Months Ended		3 Months Ended				9 Months Ended		12 Months Ended
	Feb. 28, 2015	Dec. 31, 2014	Sep. 30, 2015 USD ($) position	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($) position	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($) position
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Estimated Annual Savings									$ 11,000
Restructuring and Related Cost, Annual Savings									10,800
Restructuring charges			$ 172			$ 0	$ 1,034	$ 0
Corrosion Protection [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Estimated Annual Savings									2,000
Restructuring and Related Cost, Annual Savings									2,400
Infrastructure Solutions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Estimated Annual Savings									9,000
Restructuring and Related Cost, Annual Savings									$ 8,400
Ka-te [Member]
Restructuring Cost and Reserve [Line Items]
Period of trademark license		5 years
Gain (Loss) on Disposition of Business					$ 500
Video Injection - Instituform SAS [Member]
Restructuring Cost and Reserve [Line Items]
Period of trademark license	5 years
Gain (Loss) on Disposition of Business				$ 2,900
Insituform Linings Ltd. [Member] | Ka-te [Member]
Restructuring Cost and Reserve [Line Items]
Term of exclusive tube supply agreement		5 years
Insituform Linings Ltd. [Member] | Video Injection - Instituform SAS [Member]
Restructuring Cost and Reserve [Line Items]
Term of exclusive tube supply agreement	5 years
Restructuring Plan 2014 [Member]
Restructuring Cost and Reserve [Line Items]
Charges related to restructuring						39,953		39,953
Number of terminations since inception of restructuring plan | position			86				86		86
Number of terminations during period | position							55
Restructuring charges							$ 10,730
Total pre-tax restructuring charges to date			$ 60,200				60,200		$ 60,200
Total restructuring charges to date, net of tax			45,000				45,000		45,000
Estimated remaining restructuring costs to be incurred in 2015			500				500		500
Restructuring Plan 2014 [Member] | Corrosion Protection [Member]
Restructuring Cost and Reserve [Line Items]
Charges related to restructuring								22,200
Restructuring Plan 2014 [Member] | Infrastructure Solutions [Member]
Restructuring Cost and Reserve [Line Items]
Charges related to restructuring			1,498				10,730	17,800
Restructuring Plan 2014 [Member] | Non-cash restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Total pre-tax restructuring charges to date			48,800				48,800		48,800
Restructuring Plan 2014 [Member] | Non-cash restructuring [Member] | Corrosion Protection [Member]
Restructuring Cost and Reserve [Line Items]
Total pre-tax restructuring charges to date			22,200				22,200		22,200
Restructuring Plan 2014 [Member] | Non-cash restructuring [Member] | Infrastructure Solutions [Member]
Restructuring Cost and Reserve [Line Items]
Total pre-tax restructuring charges to date			26,600				26,600		26,600
Restructuring Plan 2014 [Member] | Cash restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Total pre-tax restructuring charges to date			11,400				11,400		$ 11,400
Restructuring Plan 2014 [Member] | Severance and benefit costs [Member]
Restructuring Cost and Reserve [Line Items]
Charges related to restructuring						0		0
Restructuring charges							866
Restructuring Plan 2014 [Member] | Severance and benefit costs [Member] | Infrastructure Solutions [Member]
Restructuring Cost and Reserve [Line Items]
Charges related to restructuring			172				866
Restructuring Plan 2014 [Member] | Other restructuring costs [Member]
Restructuring Cost and Reserve [Line Items]
Charges related to restructuring						$ 2,295		$ 2,295
Restructuring charges							7,202
Restructuring Plan 2014 [Member] | Other restructuring costs [Member] | Infrastructure Solutions [Member]
Restructuring Cost and Reserve [Line Items]
Charges related to restructuring			$ 943				$ 7,202