Fixed Assets (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, before Accumulated Depreciation and Amortization	$ 73,693,000	$ 66,507,000
Less: Accumulated depreciation and amortization	(40,670,000)	(32,846,000)
Fixed assets, net	33,023,000	33,661,000
Depreciation, Amortization and Accretion, Net	9,600,000	7,300,000	$ 7,400,000
Finance Lease, Right-of-Use Asset, before Accumulated Amortization	6,172,000	6,172,000
Finance Lease, Right-of-Use Asset, Amortization	1,232,000	1,266,000	$ 1,600,000
Finance Lease, Right-of-Use Asset, Accumulated Amortization	3,400,000	2,200,000
Telephone and computer equipment
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	7,921,000	7,556,000
Computer software
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	11,813,000	8,952,000
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	3,387,000	3,526,000
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	40,468,000	40,301,000
Airplane and related equipment
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 3,932,000	$ 0