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Fixed and Intangible Assets - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Equipment and Leasehold Improvements, Net
Depreciation and amortization expenses	$ 941	$ 1,284	$ 3,216	$ 3,729
Prepaid Expenses and Other Assets
Equipment and Leasehold Improvements, Net
Costs capitalized	2,130		2,130
Communication, Technology and Information Services
Equipment and Leasehold Improvements, Net
Amortization expense of capitalized costs	$ 113		$ 127