Schedule II Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Allowance for Doubtful Accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation Allowances and Reserves, Balance, Beginning	$ 14,234	$ 14,435	$ 15,961
Valuation Allowances and Reserves, Charged to Cost and Expense	1,403	1,087	883
Valuation Allowances and Reserves, Charged to Other Accounts	1,005	(760)	(2,302)
Valuation Allowances and Reserves, Deductions	1,093	528	107
Valuation Allowances and Reserves, Balance, Ending	15,549	14,234	14,435
Valuation Allowance of Deferred Tax Assets
Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation Allowances and Reserves, Balance, Beginning	10,730	25,435	36,263
Valuation Allowances and Reserves, Charged to Cost and Expense	9,513	0	0
Valuation Allowances and Reserves, Charged to Other Accounts	(72,170)	0	0
Valuation Allowances and Reserves, Deductions	79,556	14,705	10,828
Valuation Allowances and Reserves, Balance, Ending	$ 12,857	$ 10,730	$ 25,435

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

No definition available.

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- Definition

Total of allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SX 210.12-09)
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690

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Amount of increase in the allowances and reserves, which consist of the valuation and qualifying accounts that are either netted against the cost of an asset or that reflect a liability established to represent expected future costs, from charges to costs and expenses.

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- Definition

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Total of the deductions in a given period to allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs, representing receivables written off as uncollectible and portions of the reserves utilized, respectively.

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