Restructuring - Restructuring Reserve by Type of Cost (Details) - USD ($)	3 Months Ended		9 Months Ended		21 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Jun. 30, 2016
Restructuring Plan 2016
Restructuring Cost and Reserve [Line Items]
Non-Cash Restructuring Charges (Reversals)	$ 257,000		$ 765,000
Cash Restructuring Charges (Reversals)	1,030,000		14,026,000
Pre-tax charges (reversals) related to restructuring	1,287,000		14,791,000
Restructuring Plan 2016 | Cost of revenues
Restructuring Cost and Reserve [Line Items]
Non-Cash Restructuring Charges (Reversals)	0		0
Cash Restructuring Charges (Reversals)	130,000		189,000
Pre-tax charges (reversals) related to restructuring	130,000		189,000
Restructuring Plan 2016 | Operating expenses
Restructuring Cost and Reserve [Line Items]
Non-Cash Restructuring Charges (Reversals)	257,000		516,000
Cash Restructuring Charges (Reversals)	688,000		5,360,000
Pre-tax charges (reversals) related to restructuring	945,000		5,876,000
Restructuring Plan 2016 | Restructuring Charges
Restructuring Cost and Reserve [Line Items]
Non-Cash Restructuring Charges (Reversals)	0		0
Cash Restructuring Charges (Reversals)	212,000		8,477,000
Pre-tax charges (reversals) related to restructuring	212,000		8,477,000
Restructuring Plan 2016 | Other expense
Restructuring Cost and Reserve [Line Items]
Non-Cash Restructuring Charges (Reversals)	0		249,000
Cash Restructuring Charges (Reversals)	0		0
Pre-tax charges (reversals) related to restructuring	0		249,000
Restructuring Plan 2014
Restructuring Cost and Reserve [Line Items]
Non-Cash Restructuring Charges (Reversals)	(233,000)	$ 915,000	(465,000)	$ 4,991,000
Cash Restructuring Charges (Reversals)	(130,000)	583,000	(18,000)	5,739,000
Pre-tax charges (reversals) related to restructuring	(363,000)	1,498,000	(483,000)	10,730,000	$ 60,000,000
Restructuring Plan 2014 | Cost of revenues
Restructuring Cost and Reserve [Line Items]
Non-Cash Restructuring Charges (Reversals)	0	1,678,000	0	1,546,000
Cash Restructuring Charges (Reversals)	0	(17,000)	(14,000)	1,097,000
Pre-tax charges (reversals) related to restructuring	0	1,661,000	(14,000)	2,643,000
Restructuring Plan 2014 | Operating expenses
Restructuring Cost and Reserve [Line Items]
Non-Cash Restructuring Charges (Reversals)	(232,000)	(829,000)	(593,000)	441,000
Cash Restructuring Charges (Reversals)	(130,000)	386,000	(71,000)	3,748,000
Pre-tax charges (reversals) related to restructuring	(362,000)	(443,000)	(664,000)	4,189,000
Restructuring Plan 2014 | Restructuring Charges
Restructuring Cost and Reserve [Line Items]
Non-Cash Restructuring Charges (Reversals)	0	0	0	0
Cash Restructuring Charges (Reversals)	0	172,000	67,000	1,034,000
Pre-tax charges (reversals) related to restructuring	0	172,000	67,000	1,034,000
Restructuring Plan 2014 | Other expense
Restructuring Cost and Reserve [Line Items]
Non-Cash Restructuring Charges (Reversals)	(1,000)	66,000	128,000	3,004,000
Cash Restructuring Charges (Reversals)	0	42,000	0	(140,000)
Pre-tax charges (reversals) related to restructuring	(1,000)	$ 108,000	128,000	$ 2,864,000
Infrastructure Solutions | Restructuring Plan 2016 | Operating expenses
Restructuring Cost and Reserve [Line Items]
Pre-tax charges (reversals) related to restructuring	100,000		500,000
Infrastructure Solutions | Restructuring Plan 2016 | Restructuring Charges
Restructuring Cost and Reserve [Line Items]
Pre-tax charges (reversals) related to restructuring	0		2,600,000
Corrosion Protection | Restructuring Plan 2016 | Operating expenses
Restructuring Cost and Reserve [Line Items]
Pre-tax charges (reversals) related to restructuring	0		400,000
Corrosion Protection | Restructuring Plan 2016 | Restructuring Charges
Restructuring Cost and Reserve [Line Items]
Pre-tax charges (reversals) related to restructuring	100,000		3,200,000
Energy Services | Restructuring Plan 2016 | Operating expenses
Restructuring Cost and Reserve [Line Items]
Pre-tax charges (reversals) related to restructuring	1,000,000		4,900,000
Energy Services | Restructuring Plan 2016 | Restructuring Charges
Restructuring Cost and Reserve [Line Items]
Pre-tax charges (reversals) related to restructuring	$ 200,000		$ 2,700,000