Industry Segments Data (Narrative) (Details) $ in Thousands |
3 Months Ended | 12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
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Dec. 31, 2017
USD ($)
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Sep. 30, 2017
USD ($)
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Jun. 30, 2017
USD ($)
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Mar. 31, 2017
USD ($)
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Dec. 31, 2016
USD ($)
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Sep. 30, 2016
USD ($)
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Jun. 30, 2016
USD ($)
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Mar. 31, 2016
USD ($)
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Dec. 31, 2017
USD ($)
customer
segment
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Dec. 31, 2016
USD ($)
customer
segment
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Dec. 31, 2015
USD ($)
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| Segment Reporting Information [Line Items] | |||||||||||
| Number of operating segments | segment | 1 | ||||||||||
| Number of reportable segments | segment | 1 | 2 | |||||||||
| Percentage of long-lived assets not in US | 82.00% | ||||||||||
| Number of major customers | customer | 0 | 0 | |||||||||
| Revenues | $ | $ 235,529 | $ 231,214 | $ 224,346 | $ 228,115 | $ 232,293 | $ 236,655 | $ 233,766 | $ 231,098 | $ 919,204 | $ 933,812 | $ 978,534 |
| Customer Concentration Risk | Sales Revenue, Net | |||||||||||
| Segment Reporting Information [Line Items] | |||||||||||
| Revenues | $ | $ 130,800 | ||||||||||
| Concentration risk, percentage | 13.00% | ||||||||||
| X | ||||||||||
- Definition Number of Major Customers No definition available.
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| X | ||||||||||
- Definition Segment Reporting Information, Percentage of Long-Lived Assets Not Located in Country of Origin No definition available.
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- Definition For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- 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. No definition available.
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| X | ||||||||||
- Definition Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements. No definition available.
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| X | ||||||||||
- 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. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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- Details
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- Details
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