Property and Equipment (Schedule of Property and Equipment, at Cost) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property and equipment, at cost	$ 147,549	$ 128,822
Less: accumulated depreciation	(78,345)	(69,022)
Net property and equipment	69,204	59,800
Land
Property, Plant and Equipment [Line Items]
Property and equipment, at cost	6,521	5,761
Buildings and leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, at cost	98,140	85,660
Furniture, fixtures and equipment
Property, Plant and Equipment [Line Items]
Property and equipment, at cost	$ 42,888	$ 37,401