Property and Equipment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Total	$ 28,648		$ 28,648		$ 27,960
Accumulated depreciation	(17,686)		(17,686)		(16,125)
Property and equipment, net	10,962		10,962		11,835
Depreciation expense	800	$ 700	2,300	$ 2,100
Office equipment and software
Property, Plant and Equipment [Line Items]
Total	14,336		14,336		13,540
Leasehold Improvements
Property, Plant and Equipment [Line Items]
Total	10,362		10,362		10,593
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Total	$ 3,950		$ 3,950		$ 3,827