Fixed Assets (Details) - USD ($)	3 Months Ended		12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, before Accumulated Depreciation and Amortization	$ 76,223,000	$ 75,993,000	$ 76,223,000	$ 75,993,000
Finance Lease, Right-of-Use Asset, before Accumulated Amortization	3,737,000	6,468,000	3,737,000	6,468,000
Less: Accumulated depreciation and amortization	(52,816,000)	(50,017,000)	(52,816,000)	(50,017,000)
Fixed assets, net	23,407,000	25,976,000	23,407,000	25,976,000
Depreciation, Amortization and Accretion, Net			11,500,000	11,000,000	$ 9,600,000
Finance Lease, Right-of-Use Asset, Amortization			1,109,000	1,274,000	$ 1,232,000
Finance Lease, Right-of-Use Asset, Accumulated Amortization	3,000,000	4,700,000	3,000,000	4,700,000
Telecommunication and computer equipment
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	10,545,000	9,379,000	10,545,000	9,379,000
Computer software
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	13,684,000	13,715,000	13,684,000	13,715,000
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	4,026,000	3,607,000	4,026,000	3,607,000
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	44,193,000	42,749,000	44,193,000	42,749,000
Other Noncurrent Assets
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	38,000	75,000	$ 38,000	$ 75,000
Airplane and related equipment
Property, Plant and Equipment [Line Items]
Payments to Acquire Productive Assets		$ 4,500,000
Gain (Loss) on Disposition of Other Assets	$ 300,000