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Rental Activity (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Property Subject to or Available for Operating Lease [Line Items] |  |  |
Depreciation | $ 21,875 | $ 21,147 | $ 21,641
Operating Leases, Future Minimum Payments Receivable [Abstract] |  |  |
2019 | 7,245 |  |
2020 | 3,334 |  |
2021 | 2,763 |  |
2022 | 2,644 |  |
2023 | 1,058 |  |
Total | $ 17,044 |  |
Minimum |  |  |
Property Subject to or Available for Operating Lease [Line Items] |  |  |
Rental arrangements, original term | 6 months |  |
Maximum |  |  |
Property Subject to or Available for Operating Lease [Line Items] |  |  |
Rental arrangements, original term | 24 months |  |
Rental Equipment |  |  |
Property Subject to or Available for Operating Lease [Line Items] |  |  |
Depreciation | $ 20,900 | $ 20,000 | $ 20,200

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- Definition The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585 + Details
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