Description of Business, Basis of Presentation, and Significant Accounting Policies - Additional Information (Details)	3 Months Ended
	Mar. 31, 2014 Segment
Basis Of Presentation And Significant Accounting Policies [Line Items]
Number of Reportable Segment	1
Santander Holdings USA, Inc.
Basis Of Presentation And Significant Accounting Policies [Line Items]
Ownership percentage held by third parties	60.50%
Auto Finance Holdings Series LP
Basis Of Presentation And Significant Accounting Policies [Line Items]
Ownership percentage held by third parties	4.10%
DDFS LLC
Basis Of Presentation And Significant Accounting Policies [Line Items]
Ownership percentage held by third parties	10.00%
Other Related Parties
Basis Of Presentation And Significant Accounting Policies [Line Items]
Ownership percentage held by third parties	0.10%
Public Shareholders
Basis Of Presentation And Significant Accounting Policies [Line Items]
Ownership percentage held by third parties	25.30%