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Amounts due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer) for goods or services (including trade receivables) that have been delivered or sold in the normal course of business.

+ 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 210.5-02.3)

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-Name Regulation S-X (SX)

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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 210.5-02.3-4)

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-Publisher SEC

-Name Regulation S-X (SX)

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-Name Regulation S-X (SX)

-Number 210

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A valuation allowance for trade and other receivables due to an Entity within one year (or the normal operating cycle, whichever is longer) that are expected to be uncollectible.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 4

-Article 5

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

-Publisher FASB

-Name Accounting Standards Codification

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-Publisher FASB

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Accounts Receivable Accounts Receivable (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total accounts receivable	$ 363,104us-gaap_AccountsReceivableGrossCurrent	$ 340,026us-gaap_AccountsReceivableGrossCurrent
Less: allowance for doubtful accounts	(5,826)	(3,755)	(2,693)	(2,807)
Accounts receivable, net	357,278us-gaap_AccountsReceivableNetCurrent	336,271us-gaap_AccountsReceivableNetCurrent
Accounts receivable - trade [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total accounts receivable	304,087	275,380
Accounts receivable - grants from outside parties [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total accounts receivable	32,076	33,003
Accounts receivable - insurance and other third party claims [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total accounts receivable	$ 26,941	$ 31,643