Business Segments - Business Segment Net Sales and Income before Income Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Revenue from External Customer [Line Items]
Net sales	$ 110,988	$ 107,211	$ 221,203	$ 212,014
Income before income taxes:	3,415	1,148	1,663	2,446
Operating Segments [Member]
Revenue from External Customer [Line Items]
Net sales	110,988	107,211	221,203	212,014
Income before income taxes:	8,535	6,881	12,093	12,058
Operating Segments [Member] | Forged and Cast Mill Rolls [Member]
Revenue from External Customer [Line Items]
Net sales	72,647	73,003	146,043	144,702
Operating Segments [Member] | FEP [Member]
Revenue from External Customer [Line Items]
Net sales	3,066	4,578	6,859	9,677
Operating Segments [Member] | Forged and Cast Engineered Products [Member]
Revenue from External Customer [Line Items]
Net sales	75,713	77,581	152,902	154,379
Income before income taxes:	5,361	3,904	6,937	6,128
Operating Segments [Member] | Air and Liquid Processing [Member]
Revenue from External Customer [Line Items]
Net sales	35,275	29,630	68,301	57,635
Income before income taxes:	3,174	2,977	5,156	5,930
Operating Segments [Member] | Air Handling Systems [Member]
Revenue from External Customer [Line Items]
Net sales	14,043	8,892	26,553	18,096
Operating Segments [Member] | Heat Exchange Coils [Member]
Revenue from External Customer [Line Items]
Net sales	11,979	11,105	22,802	21,740
Operating Segments [Member] | Centrifugal Pumps [Member]
Revenue from External Customer [Line Items]
Net sales	9,253	9,633	18,946	17,799
Other Expense, Including Corporate Costs - Net [Member]
Revenue from External Customer [Line Items]
Income before income taxes:	$ (5,120)	$ (5,733)	$ (10,430)	$ (9,612)