Other Assets (Schedule of Other Assets) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Finite-Lived Intangible Assets [Line Items]
Patents, at cost	$ 6,113us-gaap_FiniteLivedPatentsGross	$ 5,401us-gaap_FiniteLivedPatentsGross
Deposits on capital items	19,011us-gaap_DepositAssets	14,091us-gaap_DepositAssets
Software development costs, at cost	2,057us-gaap_FiniteLivedIntangibleAssetsNet	2,057us-gaap_FiniteLivedIntangibleAssetsNet
Investment in equity securities		259us-gaap_EquityMethodInvestments
Other	3,111us-gaap_OtherAssetsMiscellaneous	700us-gaap_OtherAssetsMiscellaneous
Other assets	25,547us-gaap_OtherAssetsNoncurrent	18,464us-gaap_OtherAssetsNoncurrent
Patents [Member]
Finite-Lived Intangible Assets [Line Items]
Accumulated amortization	(3,364)	(3,075)
Software development [Member]
Finite-Lived Intangible Assets [Line Items]
Accumulated amortization	$ (1,381)	$ (969)

The carrying amount of the asset transferred to a third party to serve as a deposit, which typically serves as security against failure by the transferor to perform under terms of an agreement.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 17

-Article 5

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

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-Paragraph 8

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

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-Name Accounting Standards Codification

-Topic 210

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-Section S99

-Paragraph 1

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This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.12)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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

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

-Publisher FASB

-Name Accounting Standards Codification

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Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Gross carrying amount before accumulated amortization as of the balance sheet date of the costs pertaining to the exclusive legal rights granted to the owner of the patent to exploit an invention or a process for a period of time specified by law. Such costs may have been expended to directly apply and receive patent rights, or to acquire such rights.

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Amount of other miscellaneous assets.

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No definition available.

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Aggregate carrying amount, as of the balance sheet date, of noncurrent assets not separately disclosed in the balance sheet. Noncurrent assets are expected to be realized or consumed after one year (or the normal operating cycle, if longer).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

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-Subparagraph (SX 210.5-02.17)

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

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