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Summary of Significant Accounting Policies (Property and Equipment) (Details) - USD ($) | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Property, Plant and Equipment [Line Items] |  |  |
Work in process | $ 3,800,000 | $ 2,389,000 |
Depreciation | 21,875,000 | 21,147,000 | $ 21,641,000
Impairment of long-lived assets held-for-use | $ 0 | 0 | 0
Minimum |  |  |
Property, Plant and Equipment [Line Items] |  |  |
Property and equipment, estimated useful life | 3 years |  |
Maximum |  |  |
Property, Plant and Equipment [Line Items] |  |  |
Property and equipment, estimated useful life | 39 years |  |
Rental Equipment |  |  |
Property, Plant and Equipment [Line Items] |  |  |
Property and equipment, estimated useful life | 15 years |  |
Rentals |  |  |
Property, Plant and Equipment [Line Items] |  |  |
Depreciation | $ 21,588,000 | 20,861,000 | 21,325,000
Sales |  |  |
Property, Plant and Equipment [Line Items] |  |  |
Depreciation | 265,000 | 265,000 | 291,000
Service & Maintenance |  |  |
Property, Plant and Equipment [Line Items] |  |  |
Depreciation | 22,000 | 21,000 | $ 25,000
Rental Equipment |  |  |
Property, Plant and Equipment [Line Items] |  |  |
Work in process | $ 11,900,000 | $ 6,400,000 |

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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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- Definition Carrying amount, net of reserves and adjustments, as of the balance sheet date of merchandise or goods which are partially completed. This inventory is generally comprised of raw materials, labor and factory overhead costs, which require further materials, labor and overhead to be converted into finished goods, and which generally require the use of estimates to determine percentage complete and pricing. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 330 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SAB Topic 5.BB) -URI http://asc.fasb.org/extlink&oid=27011343&loc=d3e100047-122729 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(6)(a)(3)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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