Fair Value Measurements (Narrative) (Details) - Weighted Average [Member] - Fair Value, Recurring [Member] - Significant Unobservable Inputs (Level 3) [Member]	Mar. 31, 2020	Dec. 31, 2019
Inventory Related Payables [Member]
Fair Value Measurements [Line Items]
Basis	11.50%	14.70%
Inventories Carried At Market [Member]
Fair Value Measurements [Line Items]
Basis	14.90%	28.20%