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SCHEDULE 13G

Amendment No. 0
Town Sports International Hldgs Inc
Common Stock
Cusip #89214A102


Cusip #89214A102
Item 1:	Reporting Person - FMR LLC
Item 4:	Delaware
Item 5:	27,052
Item 6:	0
Item 7:	2,415,203
Item 8:	0
Item 9:	2,415,203
Item 11:	9.204%
Item 12:	    HC


Cusip #89214A102
Item 1:	Reporting Person - Edward C. Johnson 3d
Item 4:	United States of America
Item 5:	0
Item 6:	0
Item 7:	2,415,203
Item 8:	0
Item 9:	2,415,203
Item 11:	9.204%
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:

		Town Sports International Hldgs Inc

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

		5 Penn Plaza
		4th Floor
		New York, NY  10001


Item 2(a).	Name of Person Filing:

		FMR LLC

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:

		89214A102

Item 3.	This statement is filed pursuant to Rule 13d-1(b) or 13d-2(b)
and the person filing, FMR LLC, 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:	2,415,203

	(b)	Percent of Class:	9.204%

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

	(i)	sole power to vote or to direct
the vote:	27,052

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

	(iii)	sole power to dispose or to
direct the disposition of:	2,415,203

	(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 Town Sports International
Hldgs Inc.  The interest of one person, Magellan Fund, an
investment company registered under the Investment
Company Act of 1940, in the Common Stock of Town Sports
International Hldgs Inc, amounted to 1,500,000 shares or
5.717% of the total outstanding Common Stock at December
31, 2007.

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.

February 13, 2008
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.
(now known as FMR LLC) 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 LLC and an investment adviser
registered under Section 203 of the Investment Advisers Act
of 1940, is the beneficial owner of 2,391,251 shares or 9.113%
of the Common Stock outstanding of Town Sports
International Hldgs 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, Magellan
Fund, amounted to 1,500,000 shares or 5.717% of the
Common Stock outstanding. Magellan Fund has its principal
business office at 82 Devonshire Street, Boston,
Massachusetts 02109.

	Edward C. Johnson 3d and FMR LLC, through its
control of Fidelity, and the funds each has sole power to
dispose of the 2,391,251 shares owned by the Funds.

	Members of the family of Edward C. Johnson 3d,
Chairman of FMR LLC, are the predominant owners, directly
or through trusts, of Series B voting common shares of FMR
LLC, representing 49% of the voting power of FMR LLC.
The Johnson family group and all other Series B shareholders
have entered into a shareholders' voting agreement under
which all Series B voting common shares will be voted in
accordance with the majority vote of Series B voting common
shares.  Accordingly, through their ownership of voting
common shares 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 LLC.

	Neither FMR LLC nor Edward C. Johnson 3d,
Chairman of FMR LLC, 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.

	Pyramis Global Advisors Trust Company ("PGATC"),
53 State Street, Boston, Massachusetts, 02109, an indirect
wholly-owned subsidiary of FMR LLC and a bank as defined
in Section 3(a)(6) of the Securities Exchange Act of 1934, is
the beneficial owner of 23,552 shares or 0.090% of the
outstanding Common Stock of the Town Sports International
Hldgs Inc as a result of its serving as investment manager of
institutional accounts owning such shares.

	Edward C. Johnson 3d and FMR LLC, through its
control of Pyramis Global Advisors Trust Company, each has
sole dispositive power over 23,552 shares and sole power to
vote or to direct the voting of 23,552 shares of Common Stock
owned by the institutional accounts managed by PGATC as
reported above.

	Fidelity International Limited ("FIL"), Pembroke Hall,
42 Crow Lane, Hamilton, Bermuda, and various foreign-based
subsidiaries provide investment advisory and management
services to a number of non-U.S. investment companies and
certain institutional investors.  FIL, which is a qualified
institution under section 240.13d-1(b)(1) pursuant to an SEC
No-Action letter dated October 5, 2000, is the beneficial
owner of 400 shares or 0.002% of the Common Stock
outstanding of the Company.

	Partnerships controlled predominantly by members of
the family of Edward C. Johnson 3d, Chairman of FMR LLC
and FIL, or trusts for their benefit, own shares of FIL voting
stock with the right to cast approximately 47% of the total
votes which may be cast by all holders of FIL voting stock.
FMR LLC and FIL are separate and independent corporate
entities, and their Boards of Directors are generally composed
of different individuals.

	FMR LLC and FIL are of the view that they are not
acting as a "group" for purposes of Section 13(d) under the
Securities Exchange Act of 1934 (the "1934" Act) and that
they are not otherwise required to attribute to each other the
"beneficial ownership" of securities "beneficially owned" by
the other corporation within the meaning of Rule 13d-3
promulgated under the 1934 Act.  Therefore, they are of the
view that the shares held by the other corporation need not be
aggregated for purposes of Section 13(d). However, FMR
LLC is making this filing on a voluntary basis as if all of the
shares are beneficially owned by FMR LLC and FIL on a joint
basis.



	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 February 13, 2008, 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 Town Sports International Hldgs Inc at
December 31, 2007.

	FMR LLC

	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. (now
known as FMR LLC) 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

	Magellan Fund

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