Capital Lease Obligations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Capital Lease Obligations.
Capital lease obligation incurred	$ 0	$ 2,000	$ 0
Leases in property and equipment
Furniture and equipment	5,741	5,741
Accumulated depreciation	(4,379)	(3,449)
Total	$ 1,362	$ 2,292