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Summary of Significant Accounting Policies - Additional Information (Detail) | 12 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2017 USD ($) Division Segment shares | Dec. 31, 2016 USD ($) shares | Dec. 31, 2015 USD ($) | Aug. 31, 2015 shares | May 31, 2008 shares
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |
Number of divisions | Division | 4 |  |  |  |
Number of reportable segments | Segment | 4 |  |  |  |
Impairments of long-lived assets | $ 1,639,000 | $ 0 | $ 0 |  |
Period for warranties for rental equipment | 90 days |  |  |  |
Period for warranties for equipment manufactured | 1 year |  |  |  |
Property, plant and equipment depreciation expenses | $ 7,600,000 | 8,100,000 | 8,200,000 |  |
Capitalized in internal use of software | 800,000 | 200,000 |  |  |
Total advertising expenses | $ 2,900,000 | 2,900,000 | 2,800,000 |  |
Estimated useful life in years, Customer relationships | 11 years |  |  |  |
Goodwill and trade name intangible assets | $ 33,500,000 | 33,500,000 |  |  |
Goodwill and intangible assets impairment charge | $ 0 | $ 0 | 0 |  |
Common stock shares authorized for repurchase | shares |  |  |  | 2,000,000 | 2,000,000
Common stock repurchased | shares | 0 | 0 |  |  |
Shares remain authorized for repurchase | shares | 1,592,026 |  |  |  |
Unbilled receivables related to end-of-lease services | $ 30,100,000 | $ 28,100,000 |  |  |
Period for credit risk identified | 30 days |  |  |  |
Estimated fair value notes payable | $ 120,200,000 | 140,700,000 |  |  |
Recorded fair value of notes payable | 120,000,000 | 140,000,000 |  |  |
Prior period reclassification adjustment |  | 2,700,000 | $ 2,400,000 |  |
ASU 2016-09 [Member] |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |
Excess tax benefits related to share-based payments | 869,000 |  |  |  |
Decrease in net cash provided by operations and net cash used in financing activities due to retrospective application of new accounting standard |  | $ 1,066,000 |  |  |
Modular Rental Equipment [Member] |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |
Impairments of long-lived assets | $ 1,600,000 |  |  |  |

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