Fair Value Measurements (Narrative) (Details)	3 Months Ended
	Mar. 31, 2013
Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Percentage of discount on collateral for estimated cost of sales	10.00%
Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Percentage of discount on collateral for estimated cost of sales	7.00%