Business Description and Summary of Significant Accounting Policies - Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Business Description and Summary of Significant Accounting Policies
Income tax expense	$ (104)	$ (521)	$ 369	$ 240
Income tax expense (% Change)			53.80%
Effective tax rate			6.90%	18.20%
Effective tax rate (% Change)			(62.10%)