Goodwill and Intangible Assets - Goodwill / Tradename (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Goodwill [Line Items]
Goodwill, beginning balance	$ 165,861	$ 129,888
Goodwill, acquisitions and related adjustments	55,655	37,126
Goodwill, foreign currency translation	(1,353)	(1,153)
Goodwill, ending balance	220,163	165,861
Tradename, beginning balance	19,766	18,419
Tradename, acquisitions and related adjustments	10,280	1,730
Tradename, impairment	(3,340)
Tradename, foreign currency adjustments	(369)	(383)
Tradename, ending balance	26,337	19,766
Environmental Segment [Member]
Goodwill [Line Items]
Goodwill, beginning balance	55,031	22,657
Goodwill, acquisitions and related adjustments	0	32,374
Goodwill, foreign currency translation	0	0
Goodwill, ending balance	55,031	55,031
Energy Segment [Member]
Goodwill [Line Items]
Goodwill, beginning balance	17,773	14,174
Goodwill, acquisitions and related adjustments	55,655	4,752
Goodwill, foreign currency translation	(1,353)	(1,153)
Goodwill, ending balance	72,075	17,773
Fluid Handling and Filtration Segment [Member]
Goodwill [Line Items]
Goodwill, beginning balance	93,057	93,057
Goodwill, acquisitions and related adjustments	0	0
Goodwill, foreign currency translation	0	0
Goodwill, ending balance	$ 93,057	$ 93,057