Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 52,299	$ 47,793
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(25,483)	(25,494)
Property, Plant and Equipment, Net	26,816	22,299
Depreciation Expense	4,140	3,552	$ 2,300
Land, Buildings and Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	11,823	11,823
Office furnishings, leasehold improvements, computer equipment and computer software
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	30,409	25,895
Transportation and construction equipment
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 10,067	$ 10,075