Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014 Segment Product	Dec. 31, 2013	Dec. 31, 2012
Accounting Policies [Abstract]
Number of products	3
Number of reportable segments	4
Impairments of long-lived assets	$ 0	$ 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	7,800,000	7,800,000
Capitalized in internal use of software	400,000	3,500,000
Total advertising expenses	2,400,000	2,400,000	2,500,000
Deferred tax assets, valuation allowance	0
Estimated useful life (In years), Customer relationships	11 years
Goodwill and trade name intangible assets	33,500,000	33,400,000
Goodwill and intangible assets impairment charge	0	0	0
Unbilled receivables related to end-of-lease services	21,100,000	18,900,000
Period for credit risk identified	30 days
Estimated fair value notes payable	122,900,000	104,600,000
Recorded fair value of notes payable	$ 120,000,000	$ 100,000,000