Operating Segments and Related Disclosures (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Segment Reporting [Abstract]
DOT—domestic									$ 1,135,100,000	$ 900,100,000	$ 625,000,000
DOT—Latin America									183,300,000	171,100,000	156,300,000
Total operating revenue	$ 328,268,000	$ 342,317,000	$ 346,308,000	$ 301,495,000	$ 273,919,000	$ 288,714,000	$ 275,891,000	$ 232,662,000	$ 1,318,388,000	$ 1,071,186,000	$ 781,265,000
Foreign country | Total passenger revenue | Maximum
Concentration Risk [Line Items]
Concentration of risk, benchmark for revenue generated from one foreign country as a percentage of total passenger revenue, maximum									4.00%	4.00%	4.00%