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Revenue Recognition - Additional Information (Detail) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2019 | Sep. 30, 2019 | Dec. 31, 2018
Disaggregation Of Revenue [Line Items] |  |  |
Period for credit risk identified |  | 30 days |
Sales revenues totaling | $ 5.8 | $ 9.8 |
Period for warranties for rental equipment |  | 90 days |
Period for warranties for equipment manufactured |  | 1 year |
Deferred Income [Member] |  |  |
Disaggregation Of Revenue [Line Items] |  |  |
Customer contract liability | 18.6 | $ 18.6 | $ 15.7
Accounts Receivable [Member] |  |  |
Disaggregation Of Revenue [Line Items] |  |  |
Unbilled contract assets | $ 3.5 | $ 3.5 | $ 1.4

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