Summary of Significant Accounting Policies (Details 4) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Total Revenues	$ 147,591	$ 155,066	$ 152,448
Other countries less than 5% of revenues	52,197	48,574	47,793
Unites States [Member]
Total Revenues	85,682	98,496	95,757
Germany [Member]
Total Revenues	$ 9,712	$ 7,996	$ 8,898