American Express Relationship (Narrative) (Details)	9 Months Ended
Sep. 30, 2013
Future revenue increase [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Revenue Recognition, Multiple-deliverable Arrangements, Allocation to Specific Unit of Accounting, Effect of Changes, Selling Price	100
Current period change [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Revenue Recognition, Multiple-deliverable Arrangements, Allocation to Specific Unit of Accounting, Effect of Changes, Selling Price	10

Describes the effect of changes on the allocation of consideration to a specific unit of accounting caused by a change in the selling price factor applied to a multiple-deliverable arrangement.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 605

-SubTopic 25

-Section 50

-Paragraph 2

-Subparagraph (h)

-URI http://asc.fasb.org/extlink&oid=19771336&loc=SL6750900-111635

Name:	us-gaap_RevenueRecognitionMultipleDeliverableArrangementsAllocationToSpecificUnitOfAccountingEffectOfChangesSellingPrice
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration