Income Taxes Unrecognized tax benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Unrecognized tax benefits roll forward [Roll Forward]
Unrecognized Tax Benefits	$ 18,443	$ 15,027	$ 10,824	$ 6,527
Unrecognized Tax Benefits, Increases Resulting from Prior Period Tax Positions	502	138	0
Unrecognized Tax Benefits, Increases Resulting from Current Period Tax Positions	2,987	4,231	4,536
Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions	(15)	(3)	(146)
Unrecognized Tax Benefits, Reductions Resulting from Lapse of Applicable Statute of Limitations	$ (58)	$ (163)	$ (93)