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Revenue Recognition - Net Sales Disaggregated by Product Line and Geographic Area (Detail) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2019 | Dec. 31, 2018 | Sep. 30, 2018 | Jun. 30, 2018 | Mar. 31, 2018 | Dec. 31, 2017 | Sep. 30, 2017 | Jun. 30, 2017 | Mar. 31, 2019 | Mar. 31, 2018 | Mar. 31, 2017
Disaggregation Of Revenue [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net sales | $ 23,641 | $ 17,198 | $ 21,441 | $ 29,551 | $ 22,178 | $ 17,281 | $ 17,224 | $ 20,851 | $ 91,831 | $ 77,534 | $ 91,769
Asia [Member] |  |  |  |  |  |  |  |  |  |  |
Disaggregation Of Revenue [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net sales |  |  |  |  |  |  |  |  | 10,292 | 10,200 | 7,711
Canada [Member] |  |  |  |  |  |  |  |  |  |  |
Disaggregation Of Revenue [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net sales |  |  |  |  |  |  |  |  | 16,602 | 8,888 | 3,506
Middle East [Member] |  |  |  |  |  |  |  |  |  |  |
Disaggregation Of Revenue [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net sales |  |  |  |  |  |  |  |  | 2,610 | 3,785 | 3,160
South America [Member] |  |  |  |  |  |  |  |  |  |  |
Disaggregation Of Revenue [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net sales |  |  |  |  |  |  |  |  | 324 | 1,560 | 4,773
U.S. [Member] |  |  |  |  |  |  |  |  |  |  |
Disaggregation Of Revenue [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net sales |  |  |  |  |  |  |  |  | 59,441 | 51,950 | 69,166
All Other [Member] |  |  |  |  |  |  |  |  |  |  |
Disaggregation Of Revenue [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net sales |  |  |  |  |  |  |  |  | 2,562 | 1,151 | 3,453
Heat Transfer Equipment [Member] |  |  |  |  |  |  |  |  |  |  |
Disaggregation Of Revenue [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net sales |  |  |  |  |  |  |  |  | 24,785 | 27,023 | 27,616
Vacuum Equipment [Member] |  |  |  |  |  |  |  |  |  |  |
Disaggregation Of Revenue [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net sales |  |  |  |  |  |  |  |  | 34,461 | 22,175 | 29,672
All Other [Member] |  |  |  |  |  |  |  |  |  |  |
Disaggregation Of Revenue [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net sales |  |  |  |  |  |  |  |  | $ 32,585 | $ 28,336 | $ 34,481

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