Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014 segment	Jun. 30, 2013
Segment Reporting Information [Line Items]
Number of operating segments			1
Revenue	$ 21,952	$ 20,258	$ 44,274	$ 44,241
Operating costs and expenses	16,867	14,414	34,827	32,260
Other income (expense), net	44	(79)	47	226
Income before provision for income taxes	5,129	5,765	9,494	12,207
Rental
Segment Reporting Information [Line Items]
Revenue	19,465	16,721	38,254	32,728
Operating costs and expenses	7,749	6,258	15,705	13,070
Other income (expense), net	0	0	0	0
Income before provision for income taxes	11,716	10,463	22,549	19,658
Sales
Segment Reporting Information [Line Items]
Revenue	2,275	3,329	5,613	11,164
Operating costs and expenses	1,098	1,600	3,333	6,482
Other income (expense), net	0	0	0	0
Income before provision for income taxes	1,177	1,729	2,280	4,682
Service & Maintenance
Segment Reporting Information [Line Items]
Revenue	212	208	407	349
Operating costs and expenses	84	85	168	153
Other income (expense), net	0	0	0	0
Income before provision for income taxes	128	123	239	196
Corporate
Segment Reporting Information [Line Items]
Revenue	0	0	0	0
Operating costs and expenses	7,936	6,471	15,621	12,555
Other income (expense), net	44	(79)	47	226
Income before provision for income taxes	$ (7,892)	$ (6,550)	$ (15,574)	$ (12,329)

Total costs of sales and operating expenses for the period.

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- Definition

This element represents the income or loss from continuing operations attributable to the economic entity which may also be defined as revenue less expenses from ongoing operations, after income or loss from equity method investments, but before income taxes, extraordinary items, and noncontrolling interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 10

-Article 5

+ Details

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- Definition

The aggregate amount of income or expense from ancillary business-related activities (that is to say, excluding major activities considered part of the normal operations of the business).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.7)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 7

-Article 5

+ Details

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- Definition

Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues.

+ References

No definition available.

+ Details

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- Definition

Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

+ Details

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