Revenue and (Loss) Income Before Income Taxes - Net Sales and (Loss) Income Before Income Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disaggregation Of Revenue [Line Items]
Net sales	$ 81,185	$ 75,674	$ 260,413	$ 241,515
(Loss) income before income taxes	(1,175)	1,868	2,116	5,052
Forged and Cast Mill Rolls [Member]
Disaggregation Of Revenue [Line Items]
Net sales	53,778	52,080	177,918	165,502
Forged Engineered Products [Member]
Disaggregation Of Revenue [Line Items]
Net sales	7,401	2,419	17,640	8,221
Heat Exchange Coils [Member]
Disaggregation Of Revenue [Line Items]
Net sales	6,527	6,499	18,482	19,879
Centrifugal Pumps [Member]
Disaggregation Of Revenue [Line Items]
Net sales	7,096	8,580	25,138	26,888
Air Handling Systems [Member]
Disaggregation Of Revenue [Line Items]
Net sales	6,383	6,096	21,235	21,025
U.S. [Member]
Disaggregation Of Revenue [Line Items]
Net sales	44,859	38,525	133,233	118,312
(Loss) income before income taxes	(2,201)	(331)	(3,472)	(1,762)
Foreign [Member]
Disaggregation Of Revenue [Line Items]
Net sales	36,326	37,149	127,180	123,203
(Loss) income before income taxes	$ 1,026	$ 2,199	$ 5,588	$ 6,814