Litigation and Contingent Liabilities (Details)	0 Months Ended	3 Months Ended
Feb. 01, 2013 dealer	Mar. 31, 2015 dealer
Loss Contingencies [Line Items]
Loss Contingency, Claims Dismissed, Number		1
Number of dealers alleging damages	6	5

Number of plaintiffs that have filed claims pertaining to a loss contingency.

No definition available.

Name:	us-gaap_LossContingencyNumberOfPlaintiffs
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration