SCHEDULE 13G

Amendment No. 0
Renal Care Group Inc.
Common Stock
Cusip #759930100


Cusip #759930100
Item 1:	Reporting Person - FMR Corp.
Item 4:	Commonwealth of Massachusetts
Item 5:	181
Item 6:	0
Item 7:	5,081,777
Item 8:	0
Item 9:	5,081,777
Item 11:	10.501%
Item 12:	    HC


Cusip #759930100
Item 1:	Reporting Person - Edward C. Johnson 3d
Item 4:	United States of America
Item 5:	0
Item 6:	0
Item 7:	5,081,777
Item 8:	0
Item 9:	5,081,777
Item 11:	10.501%
Item 12:	IN


Cusip #759930100
Item 1:	Reporting Person - Abigail P. Johnson
Item 4:	United States of America
Item 5:	0
Item 6:	0
Item 7:	5,081,777
Item 8:	0
Item 9:	5,081,777
Item 11:	10.501%
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:

		Renal Care Group Inc.

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

		2100 West End Avenue, Suite 800
		Nashville, TN  37203

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:

		759930100

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:	5,081,777

	(b)	Percent of Class:	10.501%

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

	(i)	sole power to vote or to direct
the vote:	181

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

	(iii)	sole power to dispose or to
direct the disposition of:	5,081,777

	(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 Renal Care Group Inc..  The
interest of one person, Fidelity Low Priced Stock Fund, an
investment company registered under the Investment
Company Act of 1940, in the Common Stock of Renal Care
Group Inc., amounted to 4,278,036 shares or 8.840% of the
total outstanding Common Stock at November 30, 2002.

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

	See attached Exhibit(s) A, B.

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 Schedule
13G in connection with FMR Corp.'s beneficial ownership of
the Common Stock of Renal Care Group Inc. at November 30,
2002 is true, complete and correct.

December 10, 2002
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 5,081,596 shares or
10.500% of the Common Stock outstanding of Renal Care
Group 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
Low Priced Stock Fund, amounted to 4,278,036 shares or
8.840% of the Common Stock outstanding. Fidelity Low
Priced Stock Fund has its principal business office at 82
Devonshire Street, Boston, Massachusetts 02109.

	Edward C. Johnson 3d, FMR Corp., through its control
of Fidelity, and the funds each has sole power to dispose of the
5,081,596 shares owned by the Funds.

	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.

	Geode Capital Management, LLC, 53 State Street,
Boston, Massachusetts 02109, a Delaware limited liability
company ("Geode LLC"), is the beneficial owner of 181
shares or 0.000% of the outstanding common stock of the
Company.  Geode LLC is wholly-owned by Fidelity Investors
III Limited Partnership ("FILP III"), a Delaware limited
partnership.  Geode LLC is an investment adviser registered
under Section 203 of the Investment Advisers Act of 1940.
Fidelity Investors Management, LLC ("FIML"), a Delaware
limited liability company, is the general partner and
investment manager of FILP III, and is an investment manager
registered under Section 203 of the Investment Advisers Act
of 1940. The managers of Geode LLC, the members of FIML
and the limited partners of FILP III are certain shareholders
and employees of FMR Corp.

	Members of the Edward C. Johnson 3d family are the
predominant owners of Class B shares of common stock of
FMR Corp., representing approximately 49% of the voting
power of FMR Corp.  Mr. Johnson 3d owns 12.0% and
Abigail Johnson owns 24.5% of the aggregate outstanding
voting stock of FMR Corp.  Mr. Johnson 3d is Chairman of
FMR Corp. and Abigail P. Johnson is a Director of FMR
Corp.  The Johnson family group and all other Class B
shareholders have entered into a shareholders' voting
agreement under which all Class B shares will be voted in
accordance with the majority vote of Class 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.










	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 December 10, 2002, 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 Renal Care Group Inc. at November 30,
2002.

	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

	Abigail P. Johnson

	By   /s/Eric D. Roiter
	Eric D. Roiter
	Duly authorized under Power of Attorney
	dated December 30, 1997, by and on behalf
	of Abigail P. Johnson

	Fidelity Management & Research Company

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

	Fidelity Low Priced Stock Fund

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