Allegiant Travel (ALGT) 10-Q 6 May 15 2015 Q1 Quarterly report Financial data

Document_And_Entity_Informatio

Document And Entity Information	3 Months Ended
	Mar. 31, 2015	1-May-15
Document and Entity Information [Abstract]
Entity Registrant Name	Allegiant Travel CO
Document Type	10-Q
Current Fiscal Year End Date	-19
Entity Common Stock, Shares Outstanding		17,148,271
Amendment Flag	FALSE
Entity Central Index Key	1362468
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Well Known Seasoned Issuer	Yes
Document Period End Date	31-Mar-15
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1

Consolidated_Balance_Sheets_Cu

Consolidated Balance Sheets (Current Period Unaudited) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Current assets:
Cash and cash equivalents	$107,108	$89,610
Restricted cash	11,021	12,021
Short-term investments	295,399	269,817
Accounts receivable	13,468	14,216
Expendable parts, supplies and fuel, net of an allowance for obsolescence of $3,397 and $3,003 at March 31, 2015 and December 31, 2014, respectively	15,959	16,980
Prepaid expenses	26,858	24,306
Deferred income taxes	6,271	6,271
Other current assets	699	406
Total current assets	476,783	433,627
Property and equipment, net	775,474	738,783
Long-term investments	35,531	57,390
Investment in and advances to unconsolidated affiliates, net	1,940	1,811
Deposits and other assets	9,249	7,774
Total assets	1,298,977	1,239,385
Current liabilities:
Current maturities of long-term debt	60,758	53,819
Accounts payable	16,110	13,232
Accrued liabilities	83,390	110,802
Air traffic liability	233,761	185,315
Total current liabilities	394,019	363,168
Long-term debt and other long-term liabilities:
Long-term debt, net of current maturities	556,505	539,280
Deferred income taxes	44,865	42,872
Total liabilities	995,389	945,320
Stockholders' equity:
Common stock, par value $.001, 100,000,000 shares authorized; 22,213,050 and 22,174,241 shares issued; 17,149,448 and 17,413,307 shares outstanding, as of March 31, 2015 and December 31, 2014, respectively	22	22
Treasury stock, at cost, 5,063,602 and 4,760,934 shares at March 31, 2015 and December 31, 2014, respectively	-380,135	-325,396
Additional paid in capital	224,209	221,257
Accumulated other comprehensive income, net	2,031	1,211
Retained earnings	456,316	395,783
Total Allegiant Travel Company stockholders' equity	302,443	292,877
Noncontrolling interest	1,145	1,188
Total equity	303,588	294,065
Total liabilities and stockholders' equity	$1,298,977	$1,239,385

Consolidated_Balance_Sheets_Cu1

Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, except Share data, unless otherwise specified
Statement of Financial Position [Abstract]
Allowance for obsolescence (in dollars)	$3,397	$3,003
Common stock, par value (in dollars per share)	$0.00	$0.00
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	22,213,050	22,174,241
Common stock, shares outstanding	17,149,448	17,413,307
Treasury stock, shares	5,063,602	4,760,934

Consolidated_Statements_of_Inc

Consolidated Statements of Income (Unaudited) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Cash dividend declared per share:	$0.25	$0
OPERATING REVENUE:
Scheduled service revenue	$200,529	$203,521
Ancillary revenue:
Air-related charges	105,069	85,454
Third party products	10,797	10,629
Total ancillary revenue	115,866	96,083
Fixed fee contract revenue	4,368	2,646
Other revenue	8,478	274
Total operating revenue	329,241	302,524
OPERATING EXPENSES:
Aircraft fuel	69,626	108,949
Salary and benefits	58,553	46,439
Station operations	23,852	22,233
Maintenance and repairs	21,392	20,600
Sales and marketing	7,101	7,818
Aircraft lease rentals	718	9,429
Depreciation and amortization	24,347	18,431
Other	15,553	11,354
Total operating expenses	221,142	245,253
OPERATING INCOME	108,099	57,271
OTHER (INCOME) EXPENSE:
Loss from unconsolidated affiliates, net	4	3
Interest income	-105	-205
Interest expense	6,826	3,128
Total other expense	6,725	2,926
INCOME BEFORE INCOME TAXES	101,374	54,345
PROVISION FOR INCOME TAXES	36,551	20,270
NET INCOME	64,823	34,075
Net loss attributable to noncontrolling interest	-44	-147
NET INCOME ATTRIBUTABLE TO ALLEGIANT TRAVEL COMPANY	$64,867	$34,222
Earnings per share to common stockholders:
Basic (in Dollars per share)	$3.75	$1.87
Diluted (in Dollars per share)	$3.74	$1.86
Weighted average shares outstanding used in computing earnings per share to common stockholders:
Basic (in Shares)	17,197	18,166
Diluted (in Shares)	17,237	18,248

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (Unaudited) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Statement of Comprehensive Income [Abstract]
Net income	$64,823	$34,075
Other comprehensive income:
Net change in available-for-sale securities, net of tax effect of $(108) and $(5) for 2015 and 2014, respectively	303	8
Net change in derivatives, net of tax effect of $(584) and $0 for 2015 and 2014, respectively	994	0
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, before Tax	477
Reclassification of derivative gains into Other revenue		0
Total other comprehensive income	820	8
Total comprehensive income	65,643	34,083
Net loss attributable to noncontrolling interest	-44	-147
Comprehensive income attributable to Allegiant Travel Company	$65,687	$34,230

Consolidated_Statements_of_Com1

Consolidated Statements of Comprehensive Income (Unaudited) Consolidated Statements of Comprehensive Income (Unaudited) (Parentheticals) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Statement of Comprehensive Income (Parentheticals) [Abstract]
Other Comprehensive Income (Loss), Available-for-sale Securities, Tax	($108)	($5)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax	$584	$0

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (Unaudited) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
OPERATING ACTIVITIES:
Net income	$64,823	$34,075
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	24,347	18,431
Loss on aircraft and other equipment disposals	2,816	1,350
Provision for obsolescence of expendable parts, supplies and fuel	394	295
Amortization of deferred financing costs and original issue discount	242	149
Stock-based compensation expense	5,033	2,189
Deferred income taxes	1,993	2,048
Excess tax benefits from stock-based compensation	-1,734	-1,323
Changes in certain assets and liabilities:
Prepaid expenses	-2,552	-3,473
Other, net	2,051	-729
Accounts payable	4,612	7,427
Accrued liabilities	12,489	5,200
Air traffic liability	48,446	41,726
Net cash provided by operating activities	162,960	107,365
INVESTING ACTIVITIES:
Purchase of investment securities	-82,335	-66,086
Proceeds from maturities of investment securities	79,433	79,802
Purchase of property and equipment, including pre-delivery deposits	-64,128	-11,070
Proceeds from sale of property and equipment	274	55
Other investing activities	-129	-755
Net cash (used in) provided by investing activities	-66,885	1,946
FINANCING ACTIVITIES:
Cash dividends paid to shareholders	-48,050	-41,787
Excess tax benefits from stock-based compensation	1,734	1,323
Proceeds from exercise of stock options	0	2,240
Proceeds from the issuance of long-term debt	37,500	0
Repurchase of common stock	-54,739	-73,397
Principal payments on long-term debt	-13,336	-4,987
Other financing activities	-1,686	-296
Net cash used in financing activities	-78,577	-116,904
Net change in cash and cash equivalents	17,498	-7,593
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	89,610	97,711
CASH AND CASH EQUIVALENTS AT END OF PERIOD	$107,108	$90,118

Summary_of_Significant_Account

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2015
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies
	Basis of Presentation
	The accompanying unaudited consolidated financial statements include the accounts of Allegiant Travel Company (the “Company”) and its majority-owned operating subsidiaries. Investments in affiliates in which the Company’s ownership interest ranges from 20 to 50 percent and in which the Company has the ability to exercise significant influence over operating and financial policies are accounted for under the equity method. All intercompany balances and transactions have been eliminated.
	These unaudited consolidated financial statements reflect all normal recurring adjustments, which management believes are necessary to present fairly the financial position, results of operations, and cash flows of the Company for the respective periods presented. Certain information and footnote disclosures normally included in the annual consolidated financial statements prepared in accordance with U.S. generally accepted accounting principles ("U.S. GAAP") have been condensed or omitted pursuant to the rules and regulations of the Securities and Exchange Commission for Form 10-Q. These unaudited interim consolidated financial statements should be read in conjunction with the audited consolidated financial statements of the Company and notes thereto included in the annual report of the Company on Form 10-K for the year ended December 31, 2014, filed with the Securities and Exchange Commission.
	The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities, at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from these estimates.
	The interim results reflected in the unaudited condensed consolidated financial statements are not necessarily indicative of the results that may be expected for other interim periods or for the full year.
	Recent Accounting Pronouncements
	In May 2014, the FASB issued Accounting Standard Update ("ASU") 2014-09, intended to create a unified model to determine when and how revenue is recognized. The core principle is that a company should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration for which the entity expects to be entitled in exchange for those goods or services. On April 1, 2015, the FASB proposed deferring the effective date by one year, to December 15, 2017, for annual and interim periods beginning after that date. The FASB also proposed permitting early adoption of the standard, but not before the original effective date of December 15, 2016. The Company is evaluating the impact on its financial statements of adopting this new accounting standard.
	In April 2015, the FASB issued ASU 2015-03, which amends existing guidance and requires the presentation of debt issuance costs on the balance sheet as a reduction of the carrying amount of the related debt liability rather than a deferred charge. This ASU is effective for fiscal years, and interim periods within those years, beginning on or after December 15, 2015, and early adoption is permitted. The Company is evaluating the impact on its financial statements of adopting this new accounting standard.

Investment_Securities

Investment Securities	3 Months Ended
	Mar. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Investment Securities	Investment Securities
	The Company’s investments in marketable securities are classified as available-for-sale and are reported at fair market value with the net unrealized gain or loss reported as a component of accumulated other comprehensive income ("AOCI") in stockholders’ equity. Excluded from the table below is the change in fair value attributable to the foreign currency risk being hedged. Refer to Note 7 - Derivative Instruments for additional information related to the Company's foreign currency hedge. Investment securities are classified as cash equivalents, short-term investments, and long-term investments based on maturity date. Cash equivalents have maturities of three months or less, short-term investments have maturities of greater than three months but equal to or less than one year, and long-term investments are those with a maturity date greater than one year. Investment securities consisted of the following:
		As of March 31, 2015									As of December 31, 2014
				Net Unrealized									Net Unrealized
		Cost		Gains		(Losses)			Market Value		Cost		Gains		(Losses)			Market Value
	Money market funds	$	2,733	$	—	$	—		$	2,733	$	8,377	$	—	$	—		$	8,377
	Certificates of deposit	—		—		—			—		10,049		2		—			10,051
	Commercial paper	70,861		4		(6		)	70,859		47,941		3		(4		)	47,940
	Municipal debt securities	99,782		5		(3		)	99,784		105,933		14		(2		)	105,945
	Government debt securities	35,520		15		(4		)	35,531		24,028		—		(31		)	23,997
	Corporate debt securities	122,566		8		(38		)	122,536		134,770		1		(106		)	134,665
	Federal agency debt securities	4,704		1		—			4,705		4,711		—		(1		)	4,710
	Total	$	336,166	$	33	$	(51	)	$	336,148	$	335,809	$	20	$	(144	)	$	335,685
	The amortized cost of investment securities sold is determined by the specific identification method with any realized gains or losses reflected in other (income) expense. The Company had no realized gains or losses for the three months ended March 31, 2015 and minimal realized losses during the same period in 2014.

Property_and_Equipment

Property and Equipment	3 Months Ended
	Mar. 31, 2015
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment Disclosure	Property and Equipment
	As of March 31, 2015, the Company owned 53 MD-80 aircraft, six Boeing 757-200 aircraft, nine Airbus A320 aircraft and 18 Airbus A319 aircraft, which includes 12 Airbus A319 aircraft on lease to a third party. The Airbus A320 aircraft and Airbus A319 aircraft are frequently referred to collectively as Airbus A320 series aircraft.
	Property and equipment consisted of the following:
		As of March 31, 2015		As of December 31, 2014
	Flight equipment	$	989,994	$	947,082
	Ground property and equipment	116,891		100,916
	Total property and equipment	1,106,885		1,047,998
	Less accumulated depreciation and amortization	331,411		309,215
	Property and equipment, net	$	775,474	$	738,783
	The following table summarizes the Company's total aircraft fleet as of March 31, 2015:
	Aircraft Type		Owned (1)	Seating Capacity (per aircraft)		Average Age in Years
	MD-88/83		53	166		25.3
	B757-200		6	215		22.1
	A319 (2) (3)		5	156		10.4
	A320		9	177		14.4
	Total aircraft		73
	-1	Refer to Note 4 - Long-Term Debt for further information on the Company's notes payable secured by aircraft.
	-2	Does not include 12 Airbus A319 aircraft currently on lease to a European carrier until 2018.
	-3	Excludes one Airbus A319 aircraft owned on March 31, 2015 but placed in service during the second quarter of 2015.

LongTerm_Debt

Long-Term Debt	3 Months Ended
	Mar. 31, 2015
Debt Disclosure [Abstract]
Long-Term Debt	Long-Term Debt
	Long-term debt consisted of the following:
		As of March 31, 2015		As of December 31, 2014
	5.50% Senior Notes, due July 2019	$	300,000	$	300,000
	Notes payable, secured by aircraft, interest at LIBOR plus 3.08%, due May 2018	126,853		131,454
	Notes payable, secured by aircraft, interest at LIBOR plus 2.46%, due November 2019	40,088		41,703
	Note payable, secured by aircraft, interest at LIBOR plus 2.95%, due April 2018	35,957		38,505
	Notes payable, secured by aircraft, interest at 3.99%, due October 2018	34,555		36,844
	Notes payable, secured by aircraft, interest at LIBOR plus 2.95%, due May 2018	32,703		34,915
	Notes payable, secured by aircraft, interest at LIBOR plus 1.70%, due March 2020	30,000		—
	Note payable, secured by real estate, interest at 2.86%, due October 2018	9,607		9,678
	Note payable, secured by real estate, interest at 2.86%, due March 2020	7,500		—
	Total long-term debt	617,263		593,099
	Less current maturities	60,758		53,819
	Long-term debt, net of current maturities	$	556,505	$	539,280
	Maturities of long-term debt, as of March 31, 2015, for the remainder of 2015 and for the next four years and thereafter, in aggregate, are:
		March 31, 2015
	Remaining in 2015	$	46,691
	2016	63,458
	2017	63,659
	2018	119,069
	2019	316,354
	Thereafter	8,032
	Total	$	617,263
	Secured Debt
	In March 2015, the Company borrowed $30.0 million secured by two A319 aircraft. The notes bear interest at a floating rate based on LIBOR plus 1.70 percent, and are payable in quarterly installments through March 2020, beginning in June 2015.
	In March 2015, the Company borrowed $7.5 million secured by the real estate purchased by the Company in October 2014. The note bears a fixed interest rate of 2.86 percent per annum, and provides for a 25-year amortization and a five-year term.

Stockholders_Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2015
Equity [Abstract]
Stockholders' Equity	Stockholders’ Equity
	The Company is authorized by the Board of Directors to acquire the Company's stock through open market purchases under its share repurchase program. During the three months ended March 31, 2015, the Company repurchased 291,134 shares through open market purchases at an average price of $180.78 per share, for a total expenditure of $52,632. During the three months ended March 31, 2014, the Company repurchased 730,162 shares through open market purchases at an average price of $98.82 per share, for a total expenditure of $72,157.
	In the first quarter of 2015, the Company's Board of Directors approved a recurring quarterly cash dividend of $0.25 per share. On March 17, 2015, the Company paid cash dividends of $4,334 to shareholders of record on March 4, 2015.
	On December 3, 2014, the Company's Board of Directors declared a special cash dividend of $2.50 per share on its outstanding common stock, payable to stockholders of record on December 19, 2014. On January 6, 2015, the Company paid cash dividends of $43,703 to these shareholders.

Fair_Value_Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value, Measurement Inputs, Disclosure	Fair Value Measurements
	The Company measures certain financial assets and liabilities at fair value on a recurring basis. Fair value is an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. Accounting standards pertaining to fair value measurements establish a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows:
	Level 1 - Defined as observable inputs such as quoted prices in active markets for identical assets or liabilities
	Level 2 - Defined as inputs other than Level 1 inputs that are either directly or indirectly observable
	Level 3 - Defined as unobservable inputs for which little or no market data exists, therefore requiring an entity to develop its own assumptions.
	The Company uses the market approach valuation technique to determine fair value for investment securities. The assets classified as Level 1 consist of money market funds for which original cost approximates fair value. The assets classified as Level 2 consist of certificates of deposit, commercial paper, municipal debt securities, federal agency debt securities, government debt securities, and corporate debt securities, which are valued using quoted market prices or alternative pricing sources including transactions involving identical or comparable assets and models utilizing market observable inputs.
	For those assets classified as Level 2 that are not in active markets, the Company obtained fair value from pricing sources using quoted market prices for identical or comparable instruments and based on pricing models which include all significant observable inputs, including maturity dates, issue dates, settlement dates, benchmark yields, reported trades, broker-dealer quotes, issue spreads, benchmark securities, bids, offers and other market related data. These inputs are observable or can be derived from or corroborated by observable market data for substantially the full term of the asset.
	The fair value of the Company's derivative instrument is determined using standard valuation models. The significant inputs used in these models are readily available in public markets or can be derived from observable market transactions and therefore have been classified as Level 2. Inputs used in these standard valuation models for derivative instruments include the applicable exchange and interest rates.
	Assets measured at fair value on a recurring basis at March 31, 2015 and December 31, 2014 were as follows:
						Fair Value Measurements at Reporting Date Using
	Description		March 31, 2015			Quoted Prices in Active Markets for Identical Assets (Level 1)			Significant Other Observable Inputs (Level 2)			Significant Unobservable Inputs (Level 3)
	Cash equivalents
	Money market funds		$	2,733		$	2,733		$	—		$	—
	Municipal debt securities		2,485			—			2,485			—
	Total cash equivalents		5,218			2,733			2,485			—
	Short-term investments
	Corporate debt securities		122,536			—			122,536			—
	Municipal debt securities		97,299			—			97,299			—
	Commercial paper		70,859			—			70,859			—
	Federal agency debt securities		4,705			—			4,705			—
	Total short-term investments		295,399			—			295,399			—
	Long-term investments
	Government debt securities		35,531			—			35,531			—
	Derivative instruments		3,435			—			3,435			—
	Total long-term investments		38,966			—			38,966			—
	Total investment securities		$	339,583		$	2,733		$	336,850		$	—
						Fair Value Measurements at Reporting Date Using
	Description		December 31, 2014			Quoted Prices in Active Markets for Identical Assets (Level 1)			Significant Other Observable Inputs (Level 2)			Significant Unobservable Inputs (Level 3)
	Cash equivalents
	Money market funds		$	8,377		$	8,377		$	—		$	—
	Municipal debt securities		101			—			101			—
	Total cash equivalents		8,478			8,377			101			—
	Short-term investments
	Corporate debt securities		103,961			—			103,961			—
	Municipal debt securities		103,155			—			103,155			—
	Commercial paper		47,940			—			47,940			—
	Certificate of deposit		10,051			—			10,051			—
	Federal agency debt securities		4,710			—			4,710			—
	Total short-term investments		269,817			—			269,817			—
	Long-term investments
	Corporate debt securities		30,704			—			30,704			—
	Government debt securities		23,997			—			23,997			—
	Municipal debt securities		2,689			—			2,689			—
	Derivative instruments		1,858			—			1,858			—
	Total long-term investments		59,248			—			59,248			—
	Total investment securities		$	337,543		$	8,377		$	329,166		$	—
	The Company had no significant transfers between Level 1 and Level 2 assets for the three months ended March 31, 2015 or the year ended December 31, 2014.
	The carrying amounts and estimated fair value of the Company's long-term debt (including current maturities), as well as the applicable fair value hierarchy tier, at March 31, 2015, are presented in the table below. The fair value of the Company’s publicly held long-term debt is determined based on inputs that are readily available in public markets or can be derived from information available in publicly quoted markets; therefore, the Company has categorized its publicly held debt as Level 2. The remaining eight debt agreements are not publicly held. The Company has determined the estimated fair value of this debt to be Level 3, as certain inputs used to determine the fair value of these agreements are unobservable and, therefore, are sensitive to changes in inputs. The Company utilizes indicative pricing from counterparties and the discounted cash flow method to estimate the fair value of the Level 3 items.
		As of March 31, 2015						As of December 31, 2014
		Carrying value			Estimated fair value			Carrying value			Estimated fair value			Estimated fair value
	5.50% Senior Notes, due July 2019	$	300,000		$	309,000		$	300,000		$	304,875		Level 2
	Notes payable, secured by aircraft, interest at LIBOR plus 3.08%, due May 2018	126,853			116,233			131,454			119,809			Level 3
	Notes payable, secured by aircraft, interest at LIBOR plus 2.46%, due November 2019	40,088			37,358			41,703			38,735			Level 3
	Note payable, secured by aircraft, interest at LIBOR plus 2.95%, due April 2018	35,957			34,050			38,505			36,330			Level 3
	Notes payable, secured by aircraft, interest at 3.99%, due October 2018	34,555			32,051			36,844			34,000			Level 3
	Notes payable, secured by aircraft, interest at LIBOR plus 2.95%, due May 2018	32,703			30,954			34,915			32,923			Level 3
	Notes payable, secured by aircraft, interest at LIBOR plus 1.70%, due March 2020	30,000			28,682			—			—			Level 3
	Note payable, secured by real estate, interest at 2.86%, due October 2018	9,607			8,684			9,678			8,693			Level 3
	Note payable, secured by real estate, interest at 2.86%, due March 2020	7,500			6,570			—			—			Level 3
	Total long-term debt	$	617,263		$	603,582		$	593,099		$	575,365
	Due to the short term nature, carrying amounts of cash, cash equivalents, restricted cash, accounts receivable and accounts payable approximate fair value.

Derivative_Instruments

Derivative Instruments	3 Months Ended
	Mar. 31, 2015
Derivative Instruments [Abstract]
Derivative Instruments and Hedging Activities Disclosure	Derivative Instruments
	In 2014, the Company entered into a foreign currency swap in order to mitigate the foreign currency exchange rate risk associated with the forecasted lease revenue from 12 Airbus A320 series aircraft leased to a European carrier until 2018. The Company uses a cash flow hedge to minimize the variability in cash flows of assets or liabilities or forecasted transactions caused by fluctuations in foreign currency exchange rates. At March 31, 2015, the net change in fair value recorded in AOCI related to the unrealized gain on the hedge, was $177, when compared to the fair value at December 31, 2014.
	At inception, the Company formally designated and documented this financial instrument as a hedge of a specific underlying exposure, the risk management objective, and the strategy for undertaking the hedge transaction. The Company also assessed whether the financial instrument used in the hedging transactions was effective at offsetting changes in either the fair values or cash flows of the related underlying exposures. This assessment is monitored on at least a quarterly basis, and the change in fair market value of any ineffective portion of a financial instrument is immediately recognized into earnings. For the three months ended March 31, 2015, the Company realized $305 in net gains from its cash flow hedge into Other revenue, and as of March 31, 2015, expects $753 to be reclassified from other comprehensive income into Other revenue within the next 12 months.
	At March 31, 2015, the fair value of the Company's derivative instrument was $3,435 and is reported in the Company's consolidated balance sheet within deposits and other assets. Refer to Note 6 - Fair Value Measurements for additional information related to the estimated fair value.

Earnings_per_Share

Earnings per Share	3 Months Ended
	Mar. 31, 2015
Earnings Per Share [Abstract]
Earnings per Share	Earnings per Share
	Basic and diluted earnings per share are computed pursuant to the two-class method. Under this method, the Company attributes net income to two classes- common stock and unvested restricted stock awards. Unvested restricted stock awards granted to employees under the Company’s Long-Term Incentive Plan are considered participating securities as they receive non-forfeitable rights to cash dividends at the same rate as common stock.
	Diluted net income per share is calculated using the more dilutive of two methods. Under both methods, the exercise of employee stock options and stock-settled stock appreciation rights are assumed using the treasury stock method. The assumption of vesting of restricted stock, however, differs:
	1	Assume vesting of restricted stock using the treasury stock method.
	2	Assume unvested restricted stock awards are not vested, and allocate earnings to common shares and unvested restricted stock awards using the two-class method.
	For the three months ended March 31, 2015, the second method, which assumes unvested awards are not vested, was used in the computation because it was more dilutive than the first method. The following table sets forth the computation of net income per share, on a basic and diluted basis for the periods indicated (shares shown in the following table are in thousands):
		Three Months Ended March 31,
		2015			2014
	Basic:
	Net income attributable to Allegiant Travel Company	$	64,867		$	34,222
	Less net income allocated to participating securities	(345		)	(254		)
	Net income attributable to common stock	$	64,522		$	33,968
	Net income per share, basic	$	3.75		$	1.87
	Weighted-average shares outstanding	17,197			18,166
	Diluted:
	Net income attributable to Allegiant Travel Company	$	64,867		$	34,222
	Less net income allocated to participating securities	(344		)	(253		)
	Net income attributable to common stock	$	64,523		$	33,969
	Net income per share, diluted	$	3.74		$	1.86
	Weighted-average shares outstanding	17,197			18,166
	Dilutive effect of stock options, restricted stock and stock-settled stock appreciation rights	81			121
	Adjusted weighted-average shares outstanding under treasury stock method	17,278			18,287
	Participating securities excluded under two-class method	(41		)	(39		)
	Adjusted weighted-average shares outstanding under two-class method	17,237			18,248
	No stock awards outstanding were excluded from the computation of diluted earnings per share for the three months ended March 31, 2015 as they were all dilutive. For the three months ended March 31, 2014, anti-dilutive shares excluded from the calculation of earnings per share were not material.

Commitments_and_Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies
	The Company is subject to certain legal and administrative actions it considers routine to its business activities. The Company believes the ultimate outcome of any pending legal or administrative matters will not have a material adverse impact on its financial position, liquidity or results of operations.
	As of March 31, 2015, the Company had firm commitments to purchase the following aircraft:
	Aircraft Type		Number of Firm Commitments
	Airbus A319		12
	Airbus A320		7
	The table below summarizes the Company's commitments as of March 31, 2015 related to the acquisition of aircraft, aircraft improvements, and other non-aircraft-related operating lease obligations.
		As of March 31, 2015
	Remaining in 2015	$	151,219
	2016	120,423
	2017	73,091
	2018	2,601
	2019	4,885
	After 2019	2,585
	Total commitments	$	354,804

Related_Party

Related Party	3 Months Ended
	Mar. 31, 2015
Related Party Transactions [Abstract]
Related Party Transactions Disclosure	Related Party Transactions
	The Company leases approximately 70,000 square feet of corporate office space, under a lease that expires in April 2018, where the Company previously maintained its corporate headquarters. The Company has taken action to exercise its option to terminate this lease in May 2015. The Company also leases approximately 10,000 square feet of office space in an adjacent building which is utilized for training and other corporate purposes (expires in 2019). Both buildings are owned by limited liability companies in which the Company's Chairman and Chief Executive Officer owns a significant interest as a non-controlling member. Another member of the Company's Board of Directors also owns a minority interest in these limited liability companies. Under the terms of these agreements, the Company made rent payments totaling $688 for the three months ended March 31, 2015 and $786 for the same period in 2014.
	For the three months ended March 31, 2015, Game Plane, LLC, a wholly owned subsidiary of the Company, paid $365 in program development costs to Alpine Labs, LLC and $319 for the same period in 2014. Alpine Labs, LLC has partnered with Game Plane, LLC to produce and distribute game shows filmed on Company flights. The game shows are part of promotional efforts for the Company. The Company’s Chairman and Chief Executive Officer owns a 25 percent interest in, and is on the managing board of, Alpine Labs, LLC.
	For the three months ended March 31, 2015, the Company made payments totaling $392 to Adapt Courseware, LLC for the building of corporate training content, and none during the same period in 2014. The Company's Chairman and Chief Executive Officer owns a controlling interest in Adapt Courseware, LLC.
	GMS Racing, LLC competes in the NASCAR Camping World Truck Series and ARCA Racing Series. The Company's Chairman and Chief Executive Officer owns a controlling interest in GMS Racing, LLC. The Company has sponsored GMS Racing, LLC since 2013 and has most recently committed to $2,500 for sponsorship and branding opportunities of which $900 was paid during the three months ended March 31, 2015. No payments were made to GMS Racing, LLC during the three months ended March 31, 2014.

Subsequent_Events

Subsequent Events	3 Months Ended
	Mar. 31, 2015
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events
	In April 2015, the Company entered into a purchase agreement for three Airbus A320 series aircraft and took delivery of these aircraft.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies - (Policies)	3 Months Ended
	Mar. 31, 2015
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation
	The accompanying unaudited consolidated financial statements include the accounts of Allegiant Travel Company (the “Company”) and its majority-owned operating subsidiaries. Investments in affiliates in which the Company’s ownership interest ranges from 20 to 50 percent and in which the Company has the ability to exercise significant influence over operating and financial policies are accounted for under the equity method. All intercompany balances and transactions have been eliminated.
	These unaudited consolidated financial statements reflect all normal recurring adjustments, which management believes are necessary to present fairly the financial position, results of operations, and cash flows of the Company for the respective periods presented. Certain information and footnote disclosures normally included in the annual consolidated financial statements prepared in accordance with U.S. generally accepted accounting principles ("U.S. GAAP") have been condensed or omitted pursuant to the rules and regulations of the Securities and Exchange Commission for Form 10-Q. These unaudited interim consolidated financial statements should be read in conjunction with the audited consolidated financial statements of the Company and notes thereto included in the annual report of the Company on Form 10-K for the year ended December 31, 2014, filed with the Securities and Exchange Commission.
	The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities, at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from these estimates.
	The interim results reflected in the unaudited condensed consolidated financial statements are not necessarily indicative of the results that may be expected for other interim periods or for the full year.
New Accounting Pronouncements	Recent Accounting Pronouncements
	In May 2014, the FASB issued Accounting Standard Update ("ASU") 2014-09, intended to create a unified model to determine when and how revenue is recognized. The core principle is that a company should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration for which the entity expects to be entitled in exchange for those goods or services. On April 1, 2015, the FASB proposed deferring the effective date by one year, to December 15, 2017, for annual and interim periods beginning after that date. The FASB also proposed permitting early adoption of the standard, but not before the original effective date of December 15, 2016. The Company is evaluating the impact on its financial statements of adopting this new accounting standard.
	In April 2015, the FASB issued ASU 2015-03, which amends existing guidance and requires the presentation of debt issuance costs on the balance sheet as a reduction of the carrying amount of the related debt liability rather than a deferred charge. This ASU is effective for fiscal years, and interim periods within those years, beginning on or after December 15, 2015, and early adoption is permitted. The Company is evaluating the impact on its financial statements of adopting this new accounting standard.

Investment_Securities_Tables

Investment Securities (Tables)	3 Months Ended
	Mar. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Summary of Investment Securities	Investment securities consisted of the following:
		As of March 31, 2015									As of December 31, 2014
				Net Unrealized									Net Unrealized
		Cost		Gains		(Losses)			Market Value		Cost		Gains		(Losses)			Market Value
	Money market funds	$	2,733	$	—	$	—		$	2,733	$	8,377	$	—	$	—		$	8,377
	Certificates of deposit	—		—		—			—		10,049		2		—			10,051
	Commercial paper	70,861		4		(6		)	70,859		47,941		3		(4		)	47,940
	Municipal debt securities	99,782		5		(3		)	99,784		105,933		14		(2		)	105,945
	Government debt securities	35,520		15		(4		)	35,531		24,028		—		(31		)	23,997
	Corporate debt securities	122,566		8		(38		)	122,536		134,770		1		(106		)	134,665
	Federal agency debt securities	4,704		1		—			4,705		4,711		—		(1		)	4,710
	Total	$	336,166	$	33	$	(51	)	$	336,148	$	335,809	$	20	$	(144	)	$	335,685

Property_and_Equipment_Tables

Property and Equipment (Tables)	3 Months Ended
	Mar. 31, 2015
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment	Property and equipment consisted of the following:
		As of March 31, 2015		As of December 31, 2014
	Flight equipment	$	989,994	$	947,082
	Ground property and equipment	116,891		100,916
	Total property and equipment	1,106,885		1,047,998
	Less accumulated depreciation and amortization	331,411		309,215
	Property and equipment, net	$	775,474	$	738,783

Property_and_Equipment_Types_o

Property and Equipment Types of Commercial Aircraft (Tables)	3 Months Ended
	Mar. 31, 2015
Types of Commercial Aircraft [Abstract]
Types of Commercial Aircraft	The following table summarizes the Company's total aircraft fleet as of March 31, 2015:
	Aircraft Type	Owned (1)	Seating Capacity (per aircraft)	Average Age in Years
	MD-88/83	53	166	25.3
	B757-200	6	215	22.1
	A319 (2) (3)	5	156	10.4
	A320	9	177	14.4
	Total aircraft	73

LongTerm_Debt_Tables

Long-Term Debt (Tables)	3 Months Ended
	Mar. 31, 2015
Debt Disclosure [Abstract]
Summary of Long-Term Debt	Long-term debt consisted of the following:
		As of March 31, 2015		As of December 31, 2014
	5.50% Senior Notes, due July 2019	$	300,000	$	300,000
	Notes payable, secured by aircraft, interest at LIBOR plus 3.08%, due May 2018	126,853		131,454
	Notes payable, secured by aircraft, interest at LIBOR plus 2.46%, due November 2019	40,088		41,703
	Note payable, secured by aircraft, interest at LIBOR plus 2.95%, due April 2018	35,957		38,505
	Notes payable, secured by aircraft, interest at 3.99%, due October 2018	34,555		36,844
	Notes payable, secured by aircraft, interest at LIBOR plus 2.95%, due May 2018	32,703		34,915
	Notes payable, secured by aircraft, interest at LIBOR plus 1.70%, due March 2020	30,000		—
	Note payable, secured by real estate, interest at 2.86%, due October 2018	9,607		9,678
	Note payable, secured by real estate, interest at 2.86%, due March 2020	7,500		—
	Total long-term debt	617,263		593,099
	Less current maturities	60,758		53,819
	Long-term debt, net of current maturities	$	556,505	$	539,280

LongTerm_Debt_Schedule_of_Matu

Long-Term Debt Schedule of Maturities of Long-Term Debt (Tables)	3 Months Ended
	Mar. 31, 2015
Schedule of Maturities of Long-Term Debt [Abstract]
Schedule of Maturities of Long-term Debt	Maturities of long-term debt, as of March 31, 2015, for the remainder of 2015 and for the next four years and thereafter, in aggregate, are:
		March 31, 2015
	Remaining in 2015	$	46,691
	2016	63,458
	2017	63,659
	2018	119,069
	2019	316,354
	Thereafter	8,032
	Total	$	617,263

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Assets Measured at Fair Value On a Recurring Basis	Assets measured at fair value on a recurring basis at March 31, 2015 and December 31, 2014 were as follows:
						Fair Value Measurements at Reporting Date Using
	Description		March 31, 2015			Quoted Prices in Active Markets for Identical Assets (Level 1)			Significant Other Observable Inputs (Level 2)			Significant Unobservable Inputs (Level 3)
	Cash equivalents
	Money market funds		$	2,733		$	2,733		$	—		$	—
	Municipal debt securities		2,485			—			2,485			—
	Total cash equivalents		5,218			2,733			2,485			—
	Short-term investments
	Corporate debt securities		122,536			—			122,536			—
	Municipal debt securities		97,299			—			97,299			—
	Commercial paper		70,859			—			70,859			—
	Federal agency debt securities		4,705			—			4,705			—
	Total short-term investments		295,399			—			295,399			—
	Long-term investments
	Government debt securities		35,531			—			35,531			—
	Derivative instruments		3,435			—			3,435			—
	Total long-term investments		38,966			—			38,966			—
	Total investment securities		$	339,583		$	2,733		$	336,850		$	—
						Fair Value Measurements at Reporting Date Using
	Description		December 31, 2014			Quoted Prices in Active Markets for Identical Assets (Level 1)			Significant Other Observable Inputs (Level 2)			Significant Unobservable Inputs (Level 3)
	Cash equivalents
	Money market funds		$	8,377		$	8,377		$	—		$	—
	Municipal debt securities		101			—			101			—
	Total cash equivalents		8,478			8,377			101			—
	Short-term investments
	Corporate debt securities		103,961			—			103,961			—
	Municipal debt securities		103,155			—			103,155			—
	Commercial paper		47,940			—			47,940			—
	Certificate of deposit		10,051			—			10,051			—
	Federal agency debt securities		4,710			—			4,710			—
	Total short-term investments		269,817			—			269,817			—
	Long-term investments
	Corporate debt securities		30,704			—			30,704			—
	Government debt securities		23,997			—			23,997			—
	Municipal debt securities		2,689			—			2,689			—
	Derivative instruments		1,858			—			1,858			—
	Total long-term investments		59,248			—			59,248			—
	Total investment securities		$	337,543		$	8,377		$	329,166		$	—
Fair Value, Liabilities Measured on Recurring Basis	The Company utilizes indicative pricing from counterparties and the discounted cash flow method to estimate the fair value of the Level 3 items.
		As of March 31, 2015						As of December 31, 2014
		Carrying value			Estimated fair value			Carrying value			Estimated fair value			Estimated fair value
	5.50% Senior Notes, due July 2019	$	300,000		$	309,000		$	300,000		$	304,875		Level 2
	Notes payable, secured by aircraft, interest at LIBOR plus 3.08%, due May 2018	126,853			116,233			131,454			119,809			Level 3
	Notes payable, secured by aircraft, interest at LIBOR plus 2.46%, due November 2019	40,088			37,358			41,703			38,735			Level 3
	Note payable, secured by aircraft, interest at LIBOR plus 2.95%, due April 2018	35,957			34,050			38,505			36,330			Level 3
	Notes payable, secured by aircraft, interest at 3.99%, due October 2018	34,555			32,051			36,844			34,000			Level 3
	Notes payable, secured by aircraft, interest at LIBOR plus 2.95%, due May 2018	32,703			30,954			34,915			32,923			Level 3
	Notes payable, secured by aircraft, interest at LIBOR plus 1.70%, due March 2020	30,000			28,682			—			—			Level 3
	Note payable, secured by real estate, interest at 2.86%, due October 2018	9,607			8,684			9,678			8,693			Level 3
	Note payable, secured by real estate, interest at 2.86%, due March 2020	7,500			6,570			—			—			Level 3
	Total long-term debt	$	617,263		$	603,582		$	593,099		$	575,365
	Due to the short term nature, carrying amounts of cash, cash equivalents, restricted cash, accounts receivable and accounts payable approximate fair value.

Earnings_per_Share_Tables

Earnings per Share (Tables)	3 Months Ended
	Mar. 31, 2015
Earnings Per Share [Abstract]
Computation of Net Income Per Share, Basic and Diluted	The following table sets forth the computation of net income per share, on a basic and diluted basis for the periods indicated (shares shown in the following table are in thousands):
		Three Months Ended March 31,
		2015			2014
	Basic:
	Net income attributable to Allegiant Travel Company	$	64,867		$	34,222
	Less net income allocated to participating securities	(345		)	(254		)
	Net income attributable to common stock	$	64,522		$	33,968
	Net income per share, basic	$	3.75		$	1.87
	Weighted-average shares outstanding	17,197			18,166
	Diluted:
	Net income attributable to Allegiant Travel Company	$	64,867		$	34,222
	Less net income allocated to participating securities	(344		)	(253		)
	Net income attributable to common stock	$	64,523		$	33,969
	Net income per share, diluted	$	3.74		$	1.86
	Weighted-average shares outstanding	17,197			18,166
	Dilutive effect of stock options, restricted stock and stock-settled stock appreciation rights	81			121
	Adjusted weighted-average shares outstanding under treasury stock method	17,278			18,287
	Participating securities excluded under two-class method	(41		)	(39		)
	Adjusted weighted-average shares outstanding under two-class method	17,237			18,248

Commitments_and_Contingencies_

Commitments and Contingencies Commitments to Purchase (Tables)	3 Months Ended
	Mar. 31, 2015
Commitments to Purchase Aircraft [Abstract]
Long-term Purchase Commitment	As of March 31, 2015, the Company had firm commitments to purchase the following aircraft:
	Aircraft Type	Number of Firm Commitments
	Airbus A319	12
	Airbus A320	7

Commitments_and_Contingencies_1

Commitments and Contingencies Payments Related to Commitments to Purchase (Tables)	3 Months Ended
	Mar. 31, 2015
Payments Related to Commitments to Purchase [Abstract]
Long-term Purchase Commitment [Table Text Block]	The table below summarizes the Company's commitments as of March 31, 2015 related to the acquisition of aircraft, aircraft improvements, and other non-aircraft-related operating lease obligations.
		As of March 31, 2015
	Remaining in 2015	$	151,219
	2016	120,423
	2017	73,091
	2018	2,601
	2019	4,885
	After 2019	2,585
	Total commitments	$	354,804

Investment_Securities_Detail_I

Investment Securities (Detail) - Investment Securities (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Cost	$336,166		$335,809
Gross Unrealized Gains	33	20
Gross Unrealized Losses	-51	-144
Market Value	336,148		335,685
Money market funds
Cost	2,733		8,377
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Market Value	2,733		8,377
Certificates of Deposit
Cost	0		10,049
Gross Unrealized Gains	0	2
Gross Unrealized Losses	0	0
Market Value	0		10,051
Commercial paper
Cost	70,861		47,941
Gross Unrealized Gains	4	3
Gross Unrealized Losses	-6	-4
Market Value	70,859		47,940
Municipal debt securities
Cost	99,782		105,933
Gross Unrealized Gains	5	14
Gross Unrealized Losses	-3	-2
Market Value	99,784		105,945
Government debt securities
Cost	35,520		24,028
Gross Unrealized Gains	15	0
Gross Unrealized Losses	-4	-31
Market Value	35,531		23,997
Corporate debt securities
Cost	122,566		134,770
Gross Unrealized Gains	8	1
Gross Unrealized Losses	-38	-106
Market Value	122,536		134,665
US Government Agencies Debt Securities
Cost	4,704		4,711
Gross Unrealized Gains	1	0
Gross Unrealized Losses	0	-1
Market Value	$4,705		$4,710

Property_and_Equipment_Details

Property and Equipment (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014	Jun. 30, 2014	Apr. 30, 2015
	aircraft			aircraft
Property, Plant and Equipment [Line Items]
Assets	$1,298,977,000	$1,239,385,000
Secured Long-term Debt, Noncurrent	617,263,000	593,099,000
Number of Aircraft Owned	73
Property, Plant and Equipment, Gross	989,994,000	947,082,000
Ground property and equipment	116,891,000	100,916,000
Property, Plant and Equipment, Gross	1,106,885,000	1,047,998,000
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	-331,411,000	-309,215,000
Property, Plant and Equipment, Net	775,474,000	738,783,000
MD-80 Aircraft
Property, Plant and Equipment [Line Items]
Number of Aircraft Owned	53
Seating Capacity	166
Average Age of Aircraft	25 years 3 months 18 days
Boeing 757
Property, Plant and Equipment [Line Items]
Number of Aircraft Owned	6
Seating Capacity	215
Average Age of Aircraft	22 years 1 month 6 days
Airbus A319
Property, Plant and Equipment [Line Items]
Number Of Aircraft Committed To Purchase	12
Number of Aircraft Owned	5
Seating Capacity	156
Average Age of Aircraft	10 years 4 months 24 days
Airbus A320
Property, Plant and Equipment [Line Items]
Number Of Aircraft Committed To Purchase	7
Number of Aircraft Owned	9
Seating Capacity	177
Average Age of Aircraft	14 years 4 months 24 days
Airbus A320 Aircraft Series
Property, Plant and Equipment [Line Items]
Assets			12
Notes Payable, Three Point Zero Eight Percent, Due May Two Thousand Eighteen | Due May 2018
Property, Plant and Equipment [Line Items]
Secured Long-term Debt, Noncurrent	$126,853,000
Subsequent Event | Airbus A320 Aircraft Series
Property, Plant and Equipment [Line Items]
Number Of Aircraft Committed To Purchase				3
Total Aircraft Owned | Airbus A319
Property, Plant and Equipment [Line Items]
Number of Aircraft Owned	18

LongTerm_Debt_LongTerm_Debt_Co

Long-Term Debt Long-Term Debt - Components of Long-Term Debt (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Debt Instrument [Line Items]
Secured Long-term Debt, Noncurrent	$617,263	$593,099
Long-term Debt, Fair Value	617,263
Less current maturities	60,758	53,819
Long-term debt, net of current maturities	556,505	539,280
Due July 2019
Debt Instrument [Line Items]
Secured Long-term Debt, Noncurrent	300,000	300,000
Interest Rate	5.50%	5.50%
Due March 2020
Debt Instrument [Line Items]
Interest Rate	1.70%
Due November 2019
Debt Instrument [Line Items]
Secured Long-term Debt, Noncurrent	40,088	41,703
Interest Rate	2.46%	2.46%
Due April 2018
Debt Instrument [Line Items]
Secured Long-term Debt, Noncurrent	35,957	38,505
Interest Rate	2.95%	2.95%
Notes Payable, Three Point Zero Eight Percent, Due May Two Thousand Eighteen | Due May 2018
Debt Instrument [Line Items]
Secured Long-term Debt, Noncurrent	126,853
Interest Rate	3.08%	3.08%
Notes Payable, Three Point Nine Nine Percent, Due October Two Thousand Eighteen | Due October 2018
Debt Instrument [Line Items]
Secured Long-term Debt, Noncurrent	34,555	36,844
Interest Rate	3.99%	3.99%
Notes Payable, Two Point Nine Five Percent, Due May Two Thousand Eighteen | Due May 2018
Debt Instrument [Line Items]
Secured Long-term Debt, Noncurrent	32,703	34,915
Interest Rate	2.95%	2.95%
Notes Payable, One Point Seven Percent, Due March Two Thousand Twenty [Member] | Due March 2020
Debt Instrument [Line Items]
Secured Long-term Debt, Noncurrent	30,000	0
Interest Rate	1.70%	0.00%
Notes Payable, Two Point Eight Six Percent, Due October Two Thousand Eighteen | Due October 2018
Debt Instrument [Line Items]
Secured Long-term Debt, Noncurrent	9,607	9,678
Interest Rate	2.86%	2.86%
Notes Payable, Two Point Eight Six Percent, Due March Two Thousand Twenty [Member] | Due March 2020
Debt Instrument [Line Items]
Secured Long-term Debt, Noncurrent	$7,500	$0
Interest Rate	2.86%	0.00%

LongTerm_Debt_Detail

Long-Term Debt (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Secured Long-term Debt, Noncurrent	617,263	$593,099
Due April 2018
Secured Long-term Debt, Noncurrent	35,957	38,505
Interest Rate	2.95%	2.95%
Due July 2019
Secured Long-term Debt, Noncurrent	300,000	300,000
Interest Rate	5.50%	5.50%
Due March 2020
Interest Rate	1.70%
Notes Payable, One Point Seven Percent, Due March Two Thousand Twenty [Member] | Due March 2020
Secured Long-term Debt, Noncurrent	30,000	0
Interest Rate	1.70%	0.00%
Notes Payable, One Point Seven Percent, Due March Two Thousand Twenty [Member] | Airbus A319
Debt Instrument, Collateral	2
Notes Payable, Two Point Eight Six Percent, Due March Two Thousand Twenty [Member] | Due March 2020
Secured Long-term Debt, Noncurrent	7,500	0
Interest Rate	2.86%	0.00%
Notes Payable, Three Point Zero Eight Percent, Due May Two Thousand Eighteen | Due November 2018
Secured Long-term Debt, Noncurrent		131,454
Notes Payable, Three Point Zero Eight Percent, Due May Two Thousand Eighteen | Due May 2018
Secured Long-term Debt, Noncurrent	126,853
Interest Rate	3.08%	3.08%
Notes Payable, Two Point Nine Five Percent, Due May Two Thousand Eighteen | Due May 2018
Secured Long-term Debt, Noncurrent	32,703	34,915
Interest Rate	2.95%	2.95%
Notes Payable, Three Point Nine Nine Percent, Due October Two Thousand Eighteen | Due October 2018
Secured Long-term Debt, Noncurrent	34,555	36,844
Interest Rate	3.99%	3.99%
Notes Payable, Two Point Eight Six Percent, Due October Two Thousand Eighteen | Due October 2018
Secured Long-term Debt, Noncurrent	9,607	$9,678
Interest Rate	2.86%	2.86%

LongTerm_Debt_Schedule_of_Matu1

Long-Term Debt Schedule of Maturities of Long-Term Debt (Details) (USD $)	Mar. 31, 2015
In Thousands, unless otherwise specified
Debt Instrument [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	$46,691
Long-term Debt, Maturities, Repayments of Principal in Year Two	63,458
Long-term Debt, Maturities, Repayments of Principal in Year Three	63,659
Long-term Debt, Maturities, Repayments of Principal in Year Four	119,069
Long-term Debt, Maturities, Repayments of Principal in Year Five	316,354
Long-term Debt, Maturities, Repayments of Principal after Year Five	8,032
Long-term Debt, Fair Value	$617,263

Stockholders_Equity_Detail

Stockholders' Equity (Detail) (USD $)	0 Months Ended		3 Months Ended
	Mar. 17, 2015	Jan. 06, 2015	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Stock Repurchased During Period, Shares			291,134	730,162
Treasury Stock Acquired, Average Cost Per Share			$180.78	$98.82
Stock Repurchased During Period, Value			$52,632,000	$72,157,000
Dividends Payable, Amount Per Share			$0.25		$2.50
Dividends	$4,334	$43,703,000

Fair_Value_Measurements_Detail

Fair Value Measurements (Detail) - Fair Value Measurements at Reporting Date Using (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Investment Securities	$336,148	$335,685
Fair Value, Measurements, Recurring | Estimate of Fair Value Measurement
Cash Equivalents	5,218	8,478
Investment Securities	339,583	337,543
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1
Cash Equivalents	2,733	8,377
Investment Securities	2,733	8,377
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Cash Equivalents	2,485	101
Investment Securities	336,850	329,166
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Cash Equivalents	0	0
Investment Securities	0	0
Fair Value, Measurements, Recurring | Money market funds | Estimate of Fair Value Measurement
Cash Equivalents	2,733	8,377
Fair Value, Measurements, Recurring | Money market funds | Fair Value, Inputs, Level 1
Cash Equivalents	2,733	8,377
Fair Value, Measurements, Recurring | Money market funds | Fair Value, Inputs, Level 2
Cash Equivalents	0	0
Fair Value, Measurements, Recurring | Money market funds | Fair Value, Inputs, Level 3
Cash Equivalents	0	0
Fair Value, Measurements, Recurring | Municipal debt securities | Estimate of Fair Value Measurement
Cash Equivalents	2,485	101
Fair Value, Measurements, Recurring | Municipal debt securities | Fair Value, Inputs, Level 1
Cash Equivalents	0	0
Fair Value, Measurements, Recurring | Municipal debt securities | Fair Value, Inputs, Level 2
Cash Equivalents	2,485	101
Fair Value, Measurements, Recurring | Municipal debt securities | Fair Value, Inputs, Level 3
Cash Equivalents	0	0
Short-term Investments | Corporate debt securities | Estimate of Fair Value Measurement
Investment Securities		103,961
Short-term Investments | Corporate debt securities | Fair Value, Inputs, Level 1
Investment Securities		0
Short-term Investments | Corporate debt securities | Fair Value, Inputs, Level 2
Investment Securities		103,961
Short-term Investments | Corporate debt securities | Fair Value, Inputs, Level 3
Investment Securities		0
Short-term Investments | Fair Value, Measurements, Recurring | Estimate of Fair Value Measurement
Investment Securities	295,399	269,817
Short-term Investments | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1
Investment Securities	0	0
Short-term Investments | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Investment Securities	295,399	269,817
Short-term Investments | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Investment Securities	0	0
Short-term Investments | Fair Value, Measurements, Recurring | Commercial paper | Estimate of Fair Value Measurement
Investment Securities	70,859	47,940
Short-term Investments | Fair Value, Measurements, Recurring | Commercial paper | Fair Value, Inputs, Level 1
Investment Securities	0	0
Short-term Investments | Fair Value, Measurements, Recurring | Commercial paper | Fair Value, Inputs, Level 2
Investment Securities	70,859	47,940
Short-term Investments | Fair Value, Measurements, Recurring | Commercial paper | Fair Value, Inputs, Level 3
Investment Securities	0	0
Short-term Investments | Fair Value, Measurements, Recurring | Certificates of Deposit | Estimate of Fair Value Measurement
Investment Securities		10,051
Short-term Investments | Fair Value, Measurements, Recurring | Certificates of Deposit | Fair Value, Inputs, Level 1
Investment Securities		0
Short-term Investments | Fair Value, Measurements, Recurring | Certificates of Deposit | Fair Value, Inputs, Level 2
Investment Securities		10,051
Short-term Investments | Fair Value, Measurements, Recurring | Certificates of Deposit | Fair Value, Inputs, Level 3
Investment Securities		0
Short-term Investments | Fair Value, Measurements, Recurring | Government debt securities | Estimate of Fair Value Measurement
Investment Securities		4,710
Short-term Investments | Fair Value, Measurements, Recurring | Government debt securities | Fair Value, Inputs, Level 1
Investment Securities		0
Short-term Investments | Fair Value, Measurements, Recurring | Government debt securities | Fair Value, Inputs, Level 2
Investment Securities		4,710
Short-term Investments | Fair Value, Measurements, Recurring | Government debt securities | Fair Value, Inputs, Level 3
Investment Securities		0
Short-term Investments | Fair Value, Measurements, Recurring | Municipal debt securities | Estimate of Fair Value Measurement
Investment Securities	122,536	103,155
Short-term Investments | Fair Value, Measurements, Recurring | Municipal debt securities | Fair Value, Inputs, Level 1
Investment Securities	0	0
Short-term Investments | Fair Value, Measurements, Recurring | Municipal debt securities | Fair Value, Inputs, Level 2
Investment Securities	122,536	103,155
Short-term Investments | Fair Value, Measurements, Recurring | Municipal debt securities | Fair Value, Inputs, Level 3
Investment Securities	0	0
Short-term Investments | Fair Value, Measurements, Recurring | Corporate debt securities | Estimate of Fair Value Measurement
Investment Securities	97,299
Short-term Investments | Fair Value, Measurements, Recurring | Corporate debt securities | Fair Value, Inputs, Level 1
Investment Securities	0
Short-term Investments | Fair Value, Measurements, Recurring | Corporate debt securities | Fair Value, Inputs, Level 2
Investment Securities	97,299
Short-term Investments | Fair Value, Measurements, Recurring | Corporate debt securities | Fair Value, Inputs, Level 3
Investment Securities	0
Short-term Investments | Fair Value, Measurements, Recurring | US Government Agencies Debt Securities | Estimate of Fair Value Measurement
Investment Securities	4,705
Short-term Investments | Fair Value, Measurements, Recurring | US Government Agencies Debt Securities | Fair Value, Inputs, Level 1
Investment Securities	0
Short-term Investments | Fair Value, Measurements, Recurring | US Government Agencies Debt Securities | Fair Value, Inputs, Level 2
Investment Securities	4,705
Short-term Investments | Fair Value, Measurements, Recurring | US Government Agencies Debt Securities | Fair Value, Inputs, Level 3
Investment Securities	0
Long Term Investments | Government debt securities | Estimate of Fair Value Measurement
Investment Securities		2,689
Long Term Investments | Government debt securities | Fair Value, Inputs, Level 1
Investment Securities		0
Long Term Investments | Government debt securities | Fair Value, Inputs, Level 2
Investment Securities		2,689
Long Term Investments | Government debt securities | Fair Value, Inputs, Level 3
Investment Securities		0
Long Term Investments | US Treasury and Government | Estimate of Fair Value Measurement
Investment Securities	35,531	23,997
Long Term Investments | US Treasury and Government | Fair Value, Inputs, Level 1
Investment Securities	0	0
Long Term Investments | US Treasury and Government | Fair Value, Inputs, Level 2
Investment Securities	35,531	23,997
Long Term Investments | US Treasury and Government | Fair Value, Inputs, Level 3
Investment Securities	0	0
Long Term Investments | Fair Value, Measurements, Recurring | Estimate of Fair Value Measurement
Investment Securities	38,966	59,248
Long Term Investments | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1
Investment Securities	0	0
Long Term Investments | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Investment Securities	38,966	59,248
Long Term Investments | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Investment Securities	0	0
Long Term Investments | Fair Value, Measurements, Recurring | Corporate debt securities | Estimate of Fair Value Measurement
Investment Securities		30,704
Long Term Investments | Fair Value, Measurements, Recurring | Corporate debt securities | Fair Value, Inputs, Level 1
Investment Securities		0
Long Term Investments | Fair Value, Measurements, Recurring | Corporate debt securities | Fair Value, Inputs, Level 2
Investment Securities		30,704
Long Term Investments | Fair Value, Measurements, Recurring | Corporate debt securities | Fair Value, Inputs, Level 3
Investment Securities		0
Long Term Investments | Fair Value, Measurements, Recurring | Derivative Financial Instruments, Assets | Estimate of Fair Value Measurement
Derivative Asset	3,435	1,858
Long Term Investments | Fair Value, Measurements, Recurring | Derivative Financial Instruments, Assets | Fair Value, Inputs, Level 1
Investment Securities		0
Derivative Asset	0
Long Term Investments | Fair Value, Measurements, Recurring | Derivative Financial Instruments, Assets | Fair Value, Inputs, Level 2
Investment Securities		1,858
Derivative Asset	3,435
Long Term Investments | Fair Value, Measurements, Recurring | Derivative Financial Instruments, Assets | Fair Value, Inputs, Level 3
Investment Securities		0
Derivative Asset	$0

Fair_Value_Measurements_Estima

Fair Value Measurements Estimated Fair Value of Debt (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured Long-term Debt, Noncurrent	$617,263	$593,099
Fair Value, Measurements, Recurring | Corporate debt securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured Long-term Debt, Noncurrent	603,582	575,365
Due July 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured Long-term Debt, Noncurrent	300,000	300,000
Due July 2019 | Fair Value, Measurements, Recurring | Corporate debt securities | Fair Value, Inputs, Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured Long-term Debt, Noncurrent	309,000	304,875
Due May 2018 | Notes Payable, Three Point Zero Eight Percent, Due May Two Thousand Eighteen
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured Long-term Debt, Noncurrent	126,853
Due May 2018 | Notes Payable, Two Point Nine Five Percent, Due May Two Thousand Eighteen
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured Long-term Debt, Noncurrent	32,703	34,915
Due May 2018 | Fair Value, Measurements, Recurring | Corporate debt securities | Fair Value, Inputs, Level 3 | Notes Payable, Three Point Zero Eight Percent, Due May Two Thousand Eighteen
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured Long-term Debt, Noncurrent	116,233	119,809
Due May 2018 | Fair Value, Measurements, Recurring | Corporate debt securities | Fair Value, Inputs, Level 3 | Notes Payable, Two Point Nine Five Percent, Due May Two Thousand Eighteen
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured Long-term Debt, Noncurrent	30,954	32,923
Due March 2020 | Notes Payable, One Point Seven Percent, Due March Two Thousand Twenty [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured Long-term Debt, Noncurrent	30,000	0
Due March 2020 | Notes Payable, Two Point Eight Six Percent, Due March Two Thousand Twenty [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured Long-term Debt, Noncurrent	7,500	0
Due March 2020 | Corporate debt securities | Fair Value, Inputs, Level 3 | Notes Payable, One Point Seven Percent, Due March Two Thousand Twenty [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured Long-term Debt, Noncurrent	28,682	0
Due March 2020 | Corporate debt securities | Fair Value, Inputs, Level 3 | Notes Payable, Two Point Eight Six Percent, Due March Two Thousand Twenty [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured Long-term Debt, Noncurrent	6,570	0
Due November 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured Long-term Debt, Noncurrent	40,088	41,703
Due November 2019 | Fair Value, Measurements, Recurring | Corporate debt securities | Fair Value, Inputs, Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured Long-term Debt, Noncurrent	37,358	38,735
Due April 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured Long-term Debt, Noncurrent	35,957	38,505
Due April 2018 | Fair Value, Measurements, Recurring | Corporate debt securities | Fair Value, Inputs, Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured Long-term Debt, Noncurrent	34,050
Due April 2018 | Fair Value, Measurements, Recurring | Corporate debt securities | Fair Value, Inputs, Level 3 | Notes Payable, Three Point Nine Nine Percent, Due October Two Thousand Eighteen
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured Long-term Debt, Noncurrent		36,330
Due October 2018 | Notes Payable, Three Point Nine Nine Percent, Due October Two Thousand Eighteen
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured Long-term Debt, Noncurrent	34,555	36,844
Due October 2018 | Notes Payable, Two Point Eight Six Percent, Due October Two Thousand Eighteen
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured Long-term Debt, Noncurrent	9,607	9,678
Due October 2018 | Fair Value, Measurements, Recurring | Corporate debt securities | Fair Value, Inputs, Level 3 | Notes Payable, Three Point Nine Nine Percent, Due October Two Thousand Eighteen
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured Long-term Debt, Noncurrent	32,051	34,000
Due October 2018 | Fair Value, Measurements, Recurring | Corporate debt securities | Fair Value, Inputs, Level 3 | Notes Payable, Two Point Eight Six Percent, Due October Two Thousand Eighteen
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured Long-term Debt, Noncurrent		8,693
Secured Long-term Debt, Noncurrent	$8,684

Derivative_Instruments_Derivat

Derivative Instruments Derivative Instruments - Textuals (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014	Jun. 30, 2014
Derivative [Line Items]
Assets	$1,298,977,000	$1,239,385,000
Derivative, Gain (Loss) on Derivative, Net	305
Change in Unrealized Gain (Loss) on Foreign Currency Fair Value Hedging Instruments	177
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	753
Derivative, Notional Amount	3,435
Airbus A320 Aircraft Series
Derivative [Line Items]
Assets			$12

Earnings_per_Share_Detail_Earn

Earnings per Share (Detail) - Earnings Per Share (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Basic:
Net income attributable to Allegiant Travel Company (in Dollars)	$64,867	$34,222
Undistributed Earnings (Loss) Allocated to Participating Securities, Diluted	-344	-253
Less: Net income allocated to participating securities (in Dollars)	345	254
Net income attributable to common stock (in Dollars)	64,523	33,969
Net income per share, diluted (in Dollars per share)	$3.74	$1.86
Net income attributable to common stock (in Dollars)	$64,522	$33,968
Net income per share, basic (in Dollars per share)	$3.75	$1.87
Weighted-average shares outstanding	17,197	18,166
Dilutive effect of stock options, restricted stock and stock-settled stock appreciation rights	81	121
Adjusted weighted-average shares outstanding under treasury stock method	17,278	18,287
Participating securities excluded under two-class method	-41	-39
Two-Class Method, Weighted Average Number of Shares Outstanding, Diluted	17,237	18,248

Earnings_per_Share_Details_Tex

Earnings per Share (Details Textual)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015
Earnings per Share (Textual) [Abstract]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0

Commitments_and_Contingencies_2

Commitments and Contingencies (Detail)	Mar. 31, 2015
	aircraft
Airbus A319
Long-term Purchase Commitment [Line Items]
Number Of Aircraft Committed To Purchase	12
Airbus A320
Long-term Purchase Commitment [Line Items]
Number Of Aircraft Committed To Purchase	7

Commitments_and_Contingencies_3

Commitments and Contingencies Payments Related to Commitments to Purchase (Details) (USD $)	Mar. 31, 2015
In Thousands, unless otherwise specified
Payments Related to Commitments to Purchase [Abstract]
Unrecorded Unconditional Purchase Obligation, Due in Remainder of Fiscal Year	$151,219
Unrecorded Unconditional Purchase Obligation, Due within Two Years	120,423
Unrecorded Unconditional Purchase Obligation, Due within Three Years	73,091
Unrecorded Unconditional Purchase Obligation, Due within Four Years	2,601
Unrecorded Unconditional Purchase Obligation, Due within Five Years	4,885
Unrecorded Unconditional Purchase Obligation, Due after Five Years	2,585
Unrecorded Unconditional Purchase Obligation	$354,804

Related_Party_Details

Related Party (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Office Space
Related Party Transaction [Line Items]
Related Party Transaction, Amounts of Transaction	$688	$786
Game Plane, LLC
Related Party Transaction [Line Items]
Related Party Transaction, Amounts of Transaction	365	319
Adapt Courseware, LLC
Related Party Transaction [Line Items]
Related Party Transaction, Amounts of Transaction	392	0
GMS Racing, LLC
Related Party Transaction [Line Items]
Related Party Transaction, Amounts of Transaction	900
Building 1
Related Party Transaction [Line Items]
Related Party Transaction, Description of Transaction	70000
Building 2
Related Party Transaction [Line Items]
Related Party Transaction, Description of Transaction	10000
GMS Racing, LLC
Related Party Transaction [Line Items]
Board Approved Spending	$2,500
Chief Executive Officer | Beneficial Owner | Stock Ownership
Related Party Transaction [Line Items]
Related Party, Ownership Percentage	25.00%

Subsequent_Events_Details

Subsequent Events (Details) (Airbus A319, Subsequent Event)	Apr. 30, 2015
	aircraft
Airbus A319 | Subsequent Event
Subsequent Event [Line Items]
Number Of Aircraft Committed To Purchase	3