Revenue - Net Sales (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Disaggregation Of Revenue [Line Items]
Net sales	$ 419,432	$ 385,155
Forged and Cast Mill Rolls [Member]
Disaggregation Of Revenue [Line Items]
Net sales	270,241	254,638
Forged Engineered Products [Member]
Disaggregation Of Revenue [Line Items]
Net sales	59,289	42,645
Heat Exchange Coils [Member]
Disaggregation Of Revenue [Line Items]
Net sales	26,761	28,998
Centrifugal Pumps [Member]
Disaggregation Of Revenue [Line Items]
Net sales	35,868	35,607
Air Handling Systems [Member]
Disaggregation Of Revenue [Line Items]
Net sales	27,273	23,267
U.S. [Member]
Disaggregation Of Revenue [Line Items]
Net sales	209,536	194,982
Foreign [Member]
Disaggregation Of Revenue [Line Items]
Net sales	$ 209,896	$ 190,173