Property, Equipment and Software - Summary of Property, Equipment and Software (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment	$ 41,919	$ 44,518
Less accumulated depreciation and amortization	(18,500)	(19,335)
Property, Plant and Equipment, Gross	23,419	25,183
Land	1,490	1,490
Property, Plant and Equipment, Net	24,909	26,673
Buildings [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment	15,431	15,250
Office Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment	10,303	8,693
Computer Hardware and Software [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment	15,056	15,719
Aircraft and Other [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment	$ 1,129	$ 4,856