Business Segment Information - Property and Equipment Additions, Depreciation and Amortization and Identifiable Assets (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Segment Reporting Information [Line Items]
Property and equipment additions	$ 185	$ 90	$ 526	$ 801
Depreciation and amortization	4,274	2,714	11,217	8,103
Identifiable Assets	646,820		646,820		$ 413,793
Environmental Segment [Member]
Segment Reporting Information [Line Items]
Property and equipment additions	49	59	130	327
Depreciation and amortization	1,092	508	3,349	1,286
Identifiable Assets	136,517		136,517		133,899
Energy Segment [Member]
Segment Reporting Information [Line Items]
Property and equipment additions	66	5	245	72
Depreciation and amortization	1,526	561	2,957	1,780
Identifiable Assets	316,869		316,869		91,850
Fluid Handling and Filtration Segment [Member]
Segment Reporting Information [Line Items]
Property and equipment additions	65	26	133	359
Depreciation and amortization	1,586	1,614	4,772	4,939
Identifiable Assets	169,480		169,480		172,779
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Property and equipment additions	5		18	43
Depreciation and amortization	70	$ 31	139	$ 98
Identifiable Assets	$ 23,954		$ 23,954		$ 15,265