Commitments and Contingencies Extended Warranty (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Beginning balance	$ 114,300
Ending balance	77,000	$ 114,300
Less: current portion of unearned revenue for extended warranty	41,438	64,976
Extended Warranty [Member]
Beginning balance	31,549	33,654
Unearned revenue for new extended warranties	1,186	1,437
Unearned revenue recognized	(4,247)	(3,594)
Effect of change in exchange rates	154	52
Ending balance	28,642	31,549
Less: current portion of unearned revenue for extended warranty	4,220	4,226
Long-term unearned revenue for extended warranty within Other long-term obligations	$ 24,422	$ 27,323

Total increase or decrease in the deferred revenue liability due to currency translation.

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Amount of deferred revenue as of balance sheet date. Deferred revenue represents collections of cash or other assets related to a revenue producing activity for which revenue has not yet been recognized. Generally, an entity records deferred revenue when it receives consideration from a customer before achieving certain criteria that must be met for revenue to be recognized in conformity with GAAP.

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Amount of deferred revenue recognized for transactions arising during the current reporting period. Deferred revenue is a liability as of the balance sheet date related to a revenue producing activity for which revenue has not yet been recognized. Generally, an Entity records deferred revenue when it receives consideration from a customer before achieving certain criteria that must be met for revenue to be recognized in conformity with GAAP.

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The carrying amount of consideration received or receivable as of the balance sheet date on potential earnings that were not recognized as revenue in conformity with GAAP, and which are expected to be recognized as such within one year or the normal operating cycle, if longer, including sales, license fees, and royalties, but excluding interest income.

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The noncurrent portion of deferred revenue amount as of balance sheet date. Deferred revenue is a liability related to a revenue producing activity for which revenue has not yet been recognized, and is not expected to be recognized in the next twelve months. Generally, an entity records deferred revenue when it receives consideration from a customer before achieving certain criteria that must be met for revenue to be recognized in conformity with GAAP.

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