Income Taxes - Reconciliation (Details)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reconciliation of United States federal statutory rate to effective income tax rate
Statutory tax rate	35.00%	35.00%	35.00%
Foreign tax rate differential	(3.60%)	(12.10%)	(10.20%)
Permanent differences	(2.00%)	9.60%	12.00%
Tax contingencies	2.30%	(0.90%)	(1.10%)
Change in tax rates	1.30%	(1.60%)	0.10%
Withholding taxes	8.10%	0.60%	0.10%
State income taxes, net of federal benefits	(0.90%)	0.20%	0.10%
Purchase accounting	0.80%	0.70%	0.80%
Tax credits	(1.10%)	(4.30%)	(8.60%)
Other	(2.70%)	(1.20%)	0.60%
Change in valuation allowance for unbenefited losses	(19.20%)	15.20%	5.50%
Effective tax rate	18.00%	41.20%	34.30%