SCHEDULE 13G

Amendment No. 0 
Republic Airways Holdings Inc 
Common Stock 
Cusip #760276105 


Cusip #760276105 
Item 1:	Reporting Person - FMR Corp.
Item 4:	Delaware
Item 5:	469,300 
Item 6:	0 
Item 7:	5,305,436 
Item 8:	0 
Item 9:	5,305,436 
Item 11:	12.696% 
Item 12:	    HC


Cusip #760276105  
Item 1:	Reporting Person - Edward C. Johnson 3d 
Item 4:	United States of America
Item 5:	0 
Item 6:	0 
Item 7:	5,305,436 
Item 8:	0 
Item 9:	5,305,436 
Item 11:	12.696% 
Item 12:	IN 




	SCHEDULE 13G - TO BE INCLUDED IN 
STATEMENTS
	FILED PURSUANT TO RULE 13d-1(b) or 13d-2(b)




Item 1(a).	Name of Issuer:	

		Republic Airways Holdings Inc 

Item 1(b).	Name of Issuer's Principal Executive Offices:

		8909 Purdue Road
		Suite 300 
		Indianapolis, IN  46268
		  

Item 2(a).	Name of Person Filing: 

		FMR Corp.

Item 2(b).	Address or Principal Business Office or, if None, 
Residence:

		82 Devonshire Street, Boston, 
Massachusetts  02109

Item 2(c).	Citizenship:

		Not applicable

Item 2(d).	Title of Class of Securities:

		Common Stock 

Item 2(e).	CUSIP Number:  

		760276105 

Item 3.	This statement is filed pursuant to Rule 13d-1(b) or 13d-2(b) 
and the person filing, FMR Corp., is a parent holding company 
in accordance with Section 240.13d-1(b)(ii)(G).  (Note:  See 
Item 7).

Item 4.	Ownership

	(a)	Amount Beneficially Owned:	5,305,436 

	(b)	Percent of Class:	12.696% 

	(c)	Number of shares as to which such 
person has:  

	(i)	sole power to vote or to direct 
the vote:	469,300 

	(ii)	shared power to vote or to 
direct the vote:	0 

	(iii)	sole power to dispose or to 
direct the disposition of:	5,305,436 

	(iv)	shared power to dispose or to 
direct the disposition of:	0 



Item 5.	Ownership of Five Percent or Less of a Class.

	Not applicable.

Item 6.	Ownership of More than Five Percent on Behalf of Another 
Person.

	Various persons have the right to receive or the power to 
direct the receipt of dividends from, or the proceeds from the 
sale of, the Common Stock of Republic Airways Holdings Inc.  
The interest of one person, Fidelity Contrafund, an investment 
company registered under the Investment Company Act of 
1940, in the Common Stock of Republic Airways Holdings 
Inc, amounted to 2,259,912 shares or 5.408% of the total 
outstanding Common Stock at December 31, 2005. 

Item 7.	Identification and Classification of the Subsidiary Which 
Acquired the Security Being Reported on By the Parent 
Holding Company.

	See attached Exhibit A. 

Item 8.	Identification and Classification of Members of 
the Group.

	Not applicable.  See attached Exhibit A. 

Item 9.	Notice of Dissolution of Group.

	Not applicable.

Item 10.	Certification.

	By signing below I certify that, to the best of my knowledge 
and belief, the securities referred to above were acquired in the 
ordinary course of business and were not acquired for the 
purpose of and do not have the effect of changing or 
influencing the control of the issuer of such securities and 
were not acquired in connection with or as a participant in any 
transaction having such purpose or effect.

Signature

	After reasonable inquiry and to the best of my knowledge and 
belief, I certify that the information set forth in this statement 
is true, complete and correct. 

January 10, 2006 			
Date

/s/Eric D. Roiter			
Signature

Eric D, Roiter			
Duly authorized under Power of Attorney
dated December 30, 1997 by and on behalf of FMR Corp. and 
its direct and indirect subsidiaries


	SCHEDULE 13G - TO BE INCLUDED IN 
STATEMENTS
	FILED PURSUANT TO RULE 13d-1(b) or 13d-2(b)



	Pursuant to the instructions in Item 7 of Schedule 13G, 
Fidelity Management & Research Company ("Fidelity"), 82 
Devonshire Street, Boston, Massachusetts 02109, a wholly-
owned subsidiary of FMR Corp. and an investment adviser 
registered under Section 203 of the Investment Advisers Act 
of 1940, is the beneficial owner of 5,241,136 shares or 
12.542% of the Common Stock outstanding of Republic 
Airways Holdings Inc  ("the Company") as a result of acting 
as investment adviser to various investment companies 
registered under Section 8 of the Investment Company Act of 
1940.

	The ownership of one investment company, Fidelity 
Contrafund, amounted to 2,259,912 shares or 5.408% of the 
Common Stock outstanding. Fidelity Contrafund has its 
principal business office at 82 Devonshire Street, Boston, 
Massachusetts 02109.

	Edward C. Johnson 3d and FMR Corp., through its 
control of Fidelity, and the funds each has sole power to 
dispose of the 5,241,136 shares owned by the Funds.

	Members of the family of Edward C. Johnson 3d, 
Chairman of FMR Corp., are the predominant owners, directly 
or through trusts, of Series B shares of common stock of FMR 
Corp., representing 49% of the voting power of FMR Corp.  
The Johnson family group and all other Series B shareholders 
have entered into a shareholders' voting agreement under 
which all Series B shares will be voted in accordance with the 
majority vote of Series B shares.  Accordingly, through their 
ownership of voting common stock and the execution of the 
shareholders' voting agreement, members of the Johnson 
family may be deemed, under the Investment Company Act of 
1940, to form a controlling group with respect to FMR Corp.

	Neither FMR Corp. nor Edward C. Johnson 3d, 
Chairman of FMR Corp., has the sole power to vote or direct 
the voting of the shares owned directly by the Fidelity Funds, 
which power resides with the Funds' Boards of Trustees.  
Fidelity carries out the voting of the shares under written 
guidelines established by the Funds' Boards of Trustees.

	Fidelity Management Trust Company, 82 Devonshire 
Street, Boston, Massachusetts 02109, a wholly-owned 
subsidiary of FMR Corp. and a bank as defined in Section 
3(a)(6) of the Securities Exchange Act of 1934, is the 
beneficial owner of  64,300 shares or 0.154% of the Common 
Stock outstanding of the Company as a result of its serving as 
investment manager of the institutional account(s).

	Edward C. Johnson 3d and FMR Corp., through its 
control of Fidelity Management Trust Company, each has sole 
dispositive power over 64,300 shares and sole power to vote 
or to direct the voting of 64,300 shares of Common Stock 
owned by the institutional account(s) as reported above.



	SCHEDULE 13G - TO BE INCLUDED IN 
STATEMENTS
	FILED PURSUANT TO RULE 13d-1(b) or 13d-2(b)
	RULE 13d-1(f)(1)  AGREEMENT

	The undersigned persons, on January 10, 2006, agree 
and consent to the joint filing on their behalf of this Schedule 
13G in connection with their beneficial ownership of the 
Common Stock of Republic Airways Holdings Inc at 
December 31, 2005.

	FMR Corp.

	By /s/ Eric D. Roiter			
	Eric D. Roiter
	Duly authorized under Power of Attorney dated 
December 30, 1997, by and on behalf of FMR Corp. and its 
direct and indirect subsidiaries

	Edward C. Johnson 3d

	By /s/ Eric D. Roiter			
	Eric D. Roiter
	Duly authorized under Power of Attorney dated 
December 30, 1997, by and on behalf of Edward C. Johnson 
3d

	Fidelity Management & Research Company

	By /s/ Eric D. Roiter			
	Eric D. Roiter
	Senior V.P. and General Counsel

	Fidelity Contrafund

	By /s/ Eric D. Roiter			
	Eric D. Roiter
	Secretary