Tax Receivable Agreement (Details)	12 Months Ended
Dec. 31, 2011
Tax Receivable Agreement [Abstract]
Percentage of cash savings from pre-IPO NOLs due to pre-IPO stockholders	90.00%

Percentage of Cash Savings from Pre-Initial Public Offering Net Operating Loss Due to Pre-Initial Public Offering Stockholders

No definition available.

Name:	save_PercentageOfCashSavingsFromPreInitialPublicOfferingNetOperatingLossDueToPreInitialPublicOfferingStockholders
Namespace Prefix:	save_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration