Commitments and Contingencies Extended Warranty (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Less: current portion of unearned revenue for extended warranty	$ 79,112		$ 79,112		$ 64,976
Extended Warranty [Member]
Beginning balance	30,898	$ 33,498	31,549	$ 33,654
Unearned revenue for new extended warranties	382	433	704	1,014
Unearned revenue recognized	(1,062)	(878)	(2,067)	(1,735)
Effect of change in exchange rates	53	15	85	135
Ending balance	30,271	33,068	30,271	33,068
Less: current portion of unearned revenue for extended warranty	4,325	3,951	4,325	3,951
Long-term unearned revenue for extended warranty within other long-term obligations	$ 25,946	$ 29,117	$ 25,946	$ 29,117

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

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