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Segment Information and Concentration of Business Risk, Contracts Receivable from Significant Partners (Details) - Contracts Receivables [Member] - Credit Concentration [Member] - Significant Partners [Member] - Partner
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Significant Partners [Abstract]    
Concentration percentage 75.00% 99.00%
Number of significant partners 1 4