Fair Value Measurements (Narrative) (Details) (Weighted Average [Member], Fair Value, Measurements, Recurring [Member], Significant Unobservable Inputs (Level 3) [Member])	Mar. 31, 2014	Dec. 31, 2013
Inventory Related Payables [Member]
Fair Value Measurements [Line Items]
Basis	22.10%	13.20%
Inventories Carried At Market [Member]
Fair Value Measurements [Line Items]
Basis	20.30%	21.90%