Document And Entity Information (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Jun. 30, 2011	Feb. 10, 2012 Common Stock [Member]	Feb. 10, 2012 Nonvoting Common Stock [Member]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2011
Document Fiscal Year Focus	2011
Document Fiscal Period Focus	FY
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			67,691,819	4,827,600
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float		$ 256.1