Fixed Assets - Major Classifications of Fixed Assets and Related Useful Lives (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Fixed assets, gross	$ 71,565	$ 73,025
Less accumulated depreciation	(31,885)	(29,880)
Fixed assets, net	39,680	43,145
Land
Property, Plant and Equipment [Line Items]
Fixed assets, gross	5,892	5,892
Building and Improvements
Property, Plant and Equipment [Line Items]
Fixed assets, gross	$ 25,733	25,701
Building and Improvements | Minimum
Property, Plant and Equipment [Line Items]
Fixed assets, useful life	5 years
Building and Improvements | Maximum
Property, Plant and Equipment [Line Items]
Fixed assets, useful life	40 years
Furniture and Equipment
Property, Plant and Equipment [Line Items]
Fixed assets, gross	$ 17,285	17,084
Furniture and Equipment | Minimum
Property, Plant and Equipment [Line Items]
Fixed assets, useful life	5 years
Furniture and Equipment | Maximum
Property, Plant and Equipment [Line Items]
Fixed assets, useful life	20 years
Computer Equipment
Property, Plant and Equipment [Line Items]
Fixed assets, gross	$ 9,231	11,003
Computer Equipment | Minimum
Property, Plant and Equipment [Line Items]
Fixed assets, useful life	3 years
Computer Equipment | Maximum
Property, Plant and Equipment [Line Items]
Fixed assets, useful life	5 years
Leasehold Improvements
Property, Plant and Equipment [Line Items]
Fixed assets, gross	$ 13,424	$ 13,345
Leasehold Improvements | Minimum
Property, Plant and Equipment [Line Items]
Fixed assets, useful life	3 years
Leasehold Improvements | Maximum
Property, Plant and Equipment [Line Items]
Fixed assets, useful life	5 years