Summary of Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2018 USD ($) Division Segment shares	Dec. 31, 2017 USD ($) shares	Dec. 31, 2016 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	$ 39,000	$ 1,639,000	$ 0
Period for warranties for rental equipment	90 days
Period for warranties for equipment manufactured	1 year
Property, plant and equipment depreciation expenses	$ 8,000,000	7,600,000	8,100,000
Capitalized in internal use of software	100,000	800,000
Total advertising expenses	$ 3,200,000	2,900,000	2,900,000
Estimated useful life in years, Customer relationships	11 years
Goodwill and trade name intangible assets	$ 33,700,000	33,700,000
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	$ 32,300,000	$ 30,100,000
Period for credit risk identified	30 days
Estimated fair value notes payable	$ 99,000,000	120,200,000
Recorded fair value of notes payable	100,000,000	120,000,000
ASU 2016-02 [Member]
Summary Of Significant Accounting Policies [Line Items]
Increase in assets	10,000,000
Increase in liabilities	10,000,000
Modular Rental Equipment [Member]
Summary Of Significant Accounting Policies [Line Items]
Impairments of long-lived assets	$ 100,000	$ 1,600,000