Segment Information and Concentration of Business Risk, Revenue from Significant Partners (Details) - Contracts Receivables [Member] - Credit Concentration [Member] - Significant Partners [Member] - Partner	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Significant Partners [Abstract]
Concentration percentage	99.00%	84.00%
Number of significant partners	4	2