Summary of Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2020 USD ($) Division Segment $ / shares shares	Dec. 31, 2019 USD ($) shares	Dec. 31, 2018 USD ($) shares	Aug. 31, 2015 shares
Summary Of Significant Accounting Policies [Line Items]
Number of divisions | Division	4
Number of reportable segments | Segment	4
Impairments of long-lived assets	$ 0	$ 0	$ 39,000
Period for warranties for rental equipment	90 days
Period for warranties for equipment manufactured	1 year
Property, plant and equipment depreciation expenses	$ 8,600,000	8,200,000	8,000,000.0
Capitalized in internal use of software	100,000	3,000,000.0
Total advertising expenses	$ 3,900,000	3,600,000	3,200,000
Estimated useful life in years, Customer relationships	11 years
Goodwill and trade name intangible assets	$ 34,100,000	34,100,000
Impairment charges		0	0
Goodwill and intangible assets impairment charge	$ 0	$ 0	$ 0
Anti-dilutive securities excluded from computation of diluted earnings per share | shares	0	0	0
Common stock shares authorized for repurchase | shares				2,000,000
Common stock repurchased | shares	282,221	0	0
Average price per repurchased share | $ / shares	$ 48.25
Aggregate purchase price	$ 13,600,000
Shares remain authorized for repurchase | shares	1,309,805
Unbilled receivables related to end-of-lease services	$ 38,700,000	$ 37,200,000
Period for credit risk identified	30 days
Estimated fair value notes payable	$ 103,100,000	101,400,000
Recorded fair value of notes payable	$ 100,000,000.0	$ 100,000,000.0
Modular Rental Equipment [Member]
Summary Of Significant Accounting Policies [Line Items]
Impairments of long-lived assets			$ 100,000