Income Taxes Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Taxes [Abstract]
Unrecognized tax benefits, beginning of period	$ 54,880	$ 28,146	$ 28,615
Gross increase to positions in prior years	1,164	6,461	2,749
Gross decrease to positions in prior years	(612)	(2,512)	(1,641)
Gross increases to current period tax positions	5,071	25,741	3,008
Audit settlements	(1,116)	0	0
Decrease related to lapsing of statute of limitations	(860)	(908)	(1,715)
Effect of change in exchange rates	(901)	(2,048)	(2,870)
Unrecognized tax benefits, end of period	57,626	54,880	28,146
The amount of unrecognized tax benefits that, if recognized, would affect our effective tax rate	56,411	53,602	26,980
Net interest and penalties expense	193	880	$ 469
Accrued interest	2,473	2,105
Accrued penalties	$ 2,329	$ 2,577