Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

Name:	us-gaap_Goodwill
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Business Segment Information - Goodwill (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014	Dec. 31, 2013
Goodwill
Goodwill	$ 232,240	$ 167,547	$ 134,062
Environmental Segment [Member]
Goodwill
Goodwill	55,033	53,538
Energy Segment [Member]
Goodwill
Goodwill	79,976	16,778
Fluid Handling and Filtration Segment [Member]
Goodwill
Goodwill	$ 97,231	$ 97,231