Revenue - Net Sales and Income (Loss) from Continuing Operations before Income Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation Of Revenue [Line Items]
Net sales	$ 75,674	$ 90,872	$ 241,515	$ 300,885
Income (Loss) from Continuing Operations Before Income Taxes	1,868	(794)	5,052	(12,279)
Forged and Cast Mill Rolls [Member]
Disaggregation Of Revenue [Line Items]
Net sales	52,080	63,743	165,502	214,075
Forged Engineered Products [Member]
Disaggregation Of Revenue [Line Items]
Net sales	2,419	3,709	8,221	17,224
Heat Exchange Coils [Member]
Disaggregation Of Revenue [Line Items]
Net sales	6,499	6,586	19,879	20,397
Centrifugal Pumps [Member]
Disaggregation Of Revenue [Line Items]
Net sales	8,580	9,202	26,888	27,272
Air Handling Systems [Member]
Disaggregation Of Revenue [Line Items]
Net sales	6,096	7,632	21,025	21,917
U.S. [Member]
Disaggregation Of Revenue [Line Items]
Net sales	38,525	45,997	118,312	144,895
Income (Loss) from Continuing Operations Before Income Taxes	(331)	(315)	(1,762)	(14,231)
Foreign [Member]
Disaggregation Of Revenue [Line Items]
Net sales	37,149	44,875	123,203	155,990
Income (Loss) from Continuing Operations Before Income Taxes	$ 2,199	$ (479)	$ 6,814	$ 1,952