Commitments and Contingencies (Narrative) (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended			28 Months Ended
	Sep. 30, 2013	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Mar. 31, 2017
Commitments and Contingencies (Details) [Line Items]
Rent expense		$ 2,000	$ 1,500	$ 831
Tax protection agreements, period (in years)					10 years
Terranomics Crossroads Associates LP Member and SARM Five Points LLC [Member]
Commitments and Contingencies (Details) [Line Items]
Tax protection agreements, period (in years)	12 years