Acquisitions - Fair Values of Assets and Liabilities Assumed at Date of Closing - PMFG (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Sep. 03, 2015	Dec. 31, 2014	Dec. 31, 2013
Business Acquisition [Line Items]
Goodwill	$ 220,163		$ 165,861	$ 129,888
PMFG, Inc. [Member]
Business Acquisition [Line Items]
Current assets (including cash of $27,100)		$ 93,884
Property and equipment		30,252
Other assets		953
Assets held for sale		950
Goodwill		55,655
Intangible – finite life		29,940
Intangible – indefinite life		10,280
Total assets acquired		221,914
Current liabilities assumed		(73,328)
Deferred income tax liability		(1,899)
Long term liabilities assumed		(3,961)
Noncontrolling interest		(6,000)
Net assets acquired		$ 136,726