Business Segment Information - Intra-Segment and Inter-Segment Revenues (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Segment Reporting Information [Line Items]
Net sales	$ 78,680	$ 75,170	$ 150,572	$ 155,656
Engineered Systems Segment [Member]
Segment Reporting Information [Line Items]
Net sales	43,360	49,074	85,417	99,720
Industrial Process Solutions Segment [Member]
Segment Reporting Information [Line Items]
Net sales	35,320	26,096	65,155	55,936
Intra - Segment Sales [Member]
Segment Reporting Information [Line Items]
Net sales	(8,794)	(6,919)	(13,942)	(15,391)
Intra - Segment Sales [Member] | Engineered Systems Segment [Member]
Segment Reporting Information [Line Items]
Net sales	(3,513)	(2,984)	(5,887)	(7,790)
Intra - Segment Sales [Member] | Industrial Process Solutions Segment [Member]
Segment Reporting Information [Line Items]
Net sales	(5,281)	(3,935)	(8,055)	(7,601)
Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales	88,314	82,807	165,723	172,306
Operating Segments [Member] | Engineered Systems Segment [Member]
Segment Reporting Information [Line Items]
Net sales	47,069	52,369	91,545	107,978
Operating Segments [Member] | Industrial Process Solutions Segment [Member]
Segment Reporting Information [Line Items]
Net sales	41,245	30,438	74,178	64,328
Inter-segment Elimination [Member] | Industrial Inter-Segment Sales [Member]
Segment Reporting Information [Line Items]
Net sales	(196)	(311)	(241)	(468)
Inter-segment Elimination [Member] | Energy Inter Segment Sales
Segment Reporting Information [Line Items]
Net sales	(644)	(407)	(968)	(791)
Inter-segment Elimination [Member] | Engineered Systems Segment [Member] | Industrial Inter-Segment Sales [Member]
Segment Reporting Information [Line Items]
Net sales	(196)	(311)	(241)	(468)
Inter-segment Elimination [Member] | Industrial Process Solutions Segment [Member] | Energy Inter Segment Sales
Segment Reporting Information [Line Items]
Net sales	$ (644)	$ (407)	$ (968)	$ (791)