Business Segment Information - Property and Equipment Additions, Depreciation and Amortization and Identifiable Assets (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Segment Reporting Information [Line Items]
Property and equipment additions	$ 212	$ 119
Depreciation and amortization	5,195	3,452
Identifiable Assets	581,898		$ 598,819
Environmental Segment [Member]
Segment Reporting Information [Line Items]
Property and equipment additions	113	64
Depreciation and amortization	967	1,153
Identifiable Assets	126,110		135,171
Energy Segment [Member]
Segment Reporting Information [Line Items]
Property and equipment additions	86	40
Depreciation and amortization	2,802	671
Identifiable Assets	278,360		283,002
Fluid Handling and Filtration Segment [Member]
Segment Reporting Information [Line Items]
Property and equipment additions	9	5
Depreciation and amortization	1,394	1,596
Identifiable Assets	160,286		161,394
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Property and equipment additions	4	10
Depreciation and amortization	32	$ 32
Identifiable Assets	$ 17,142		$ 19,252