Accounts and Notes Receivable and Credit Quality of Notes Receivable - Concentration Risk (Details) (Geographic concentration risk, Notes receivable)	6 Months Ended
	Jun. 30, 2014
Peru
Concentration Risk [Line Items]
Concentration risk percentage	23.00%
Mexico
Concentration Risk [Line Items]
Concentration risk percentage	17.00%
Argentina
Concentration Risk [Line Items]
Concentration risk percentage	13.00%
Colombia
Concentration Risk [Line Items]
Concentration risk percentage	8.00%
Other (less than 5% individually)
Concentration Risk [Line Items]
Concentration risk percentage	10.00%
Total international notes receivable as a percentage of total notes receivable
Concentration Risk [Line Items]
Concentration risk percentage	71.00%