Property and Equipment - Property and Equipment (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 14,887,000	$ 15,578,000
Less accumulated depreciation	(12,196,000)	(13,183,000)
Property and equipment, net	2,691,000	2,395,000
Depreciation expense	868,000	1,045,000	$ 1,110,000
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	3,063,000	2,258,000
Office furniture, fixtures and equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 11,660,000	12,046,000
Office furniture, fixtures and equipment | Minimum
Property Plant And Equipment [Line Items]
Depreciable life	2 years
Office furniture, fixtures and equipment | Maximum
Property Plant And Equipment [Line Items]
Depreciable life	10 years
Equipment Under Capital Leases
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 164,000	$ 1,274,000