Nature of Operations and Summary of Significant Accounting Policies (Details 5) (USD $)	3 Months Ended								12 Months Ended			1 Months Ended	12 Months Ended								1 Months Ended		1 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 segment subsidiary	Dec. 31, 2011 subsidiary segment	Dec. 31, 2010	Dec. 31, 2007 Delta Connection Agreements	Dec. 31, 2012 Delta Connection Agreements Y agreement Rate	Feb. 10, 2010 Delta Connection Agreements aircraft	Sep. 30, 2012 Delta Connection Agreements CRJ 200 aircraft	Aug. 02, 2012 Delta Connection Agreements CRJ 200 aircraft	Sep. 30, 2012 Delta Connection Agreements CRJ 700s aircraft	Aug. 02, 2012 Delta Connection Agreements CRJ 700s aircraft	Sep. 30, 2012 Delta Connection Agreements CRJ 900 aircraft	Aug. 02, 2012 Delta Connection Agreements CRJ 900 aircraft	Feb. 28, 2010 United Express Agreements Y	Nov. 12, 2010 ExpressJet Capacity Purchase Agreements aircraft	Sep. 30, 2012 American Agreement Y	Feb. 14, 2013 American Agreement CRJ 200 ExpressJet aircraft	Nov. 14, 2012 American Agreement CRJ 200 SkyWest Airlines, Inc. aircraft
Agreements with other airlines
Term of agreement (in years)													15								5		4
Number of agreements for cross-termination rights													2
Number of years after which the rate resets													5
Anniversary of agreements which contractual rates shall not exceed the second lowest rate for all carriers (in years)													5
Contractual rate shall not exceed this number of rates from other carriers													2
Number of aircraft operated														14				5		29		227			12
Number of aircraft terminated																66
Number of aircraft delivered																	5		15
Number of aircraft subleased															41
Number of aircraft anticipate to operate																								11
Amount of receivables withheld from weekly scheduled wire payments to SkyWest Airlines and Atlantic Southeast												$ 25,000,000
Other Revenue Items
Deemed rental income under code-share agreement									506,700,000	521,300,000	492,700,000
Net Income Per Common Share
Number of outstanding options not included in computation of Diluted EPS (in shares)									3,889,000	4,323,000	4,183,000
Numerator
Net (loss) income	13,946,000	20,933,000	16,960,000	(682,000)	(17,967,000)	116,000	1,579,000	(11,063,000)	51,157,000	(27,335,000)	96,350,000
Denominator
Denominator for basic earnings per-share weighted average shares	51,296,000	51,241,000	50,944,000	50,881,000	50,691,000	51,570,000	52,698,000	53,844,000	51,090,000	52,201,000	55,610,000
Dilution due to stock options and restricted stock (in shares)									656,000		916,000
Denominator for diluted earnings per-share weighted average shares	52,161,000	52,153,000	51,789,000	50,881,000	50,691,000	52,315,000	53,371,000	53,844,000	51,746,000	52,201,000	56,526,000
Basic earnings (loss) per share (in dollars per share)	$ 0.27	$ 0.41	$ 0.33	$ (0.01)	$ (0.35)	$ 0.00	$ 0.03	$ (0.21)	$ 1.00	$ (0.52)	$ 1.73
Diluted earnings (loss) per share (in dollars per share)	$ 0.27	$ 0.40	$ 0.33	$ (0.01)	$ (0.35)	$ 0.00	$ 0.03	$ (0.21)	$ 0.99	$ (0.52)	$ 1.70
COMPREHENSIVE INCOME (LOSS):
Net income (loss)	13,946,000	20,933,000	16,960,000	(682,000)	(17,967,000)	116,000	1,579,000	(11,063,000)	51,157,000	(27,335,000)	96,350,000
Proportionate share of other companies foreign currency translation adjustment, net of taxes									(251,000)	(295,000)	637,000
Net unrealized appreciation (depreciation) on marketable securities, net of taxes									316,000	534,000	(745,000)
TOTAL COMPREHENSIVE INCOME (LOSS)									51,222,000	(27,096,000)	96,242,000
Segment Reporting
Operating segments number									2	2
Number of operating subsidiaries representing operating segments									2	2
Fair Value of Financial Instruments
Fair value of long-term debt	1,744,200,000				1,952,500,000				1,744,200,000	1,952,500,000
Carrying amount of long-term debt	$ 1,642,022,000				$ 1,815,391,000				$ 1,642,022,000	$ 1,815,391,000