Document	9 Months Ended
	Sep. 30, 2012	Oct. 17, 2012 Voting Common Stock [Member]	Oct. 17, 2012 Non-Voting Common Stock [Member]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2012
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	Q3
Entity Registrant Name	SPIRIT AIRLINES, INC.
Entity Central Index Key	0001498710
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		70,859,051	1,669,205