Income Taxes Provision for Taxes (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current:
Federal									$ 0	$ 0	$ 0
State taxes									90	262	379
Foreign taxes									2,865	17,926	4,421
Total current									2,955	18,188	4,800
Deferred:
Federal									0	0	0
State taxes									0	0	0
Total deferred									0	0	0
(Provision) benefit for income taxes	$ 20	$ 216	$ 1,478	$ 1,241	$ 2,414	$ 9,655	$ 5,927	$ 192	$ 2,955	$ 18,188	$ 4,800