Filed Pursuant to Rule 424(b)(3)
Registration No. 333-139445

PROSPECTUS SUPPLEMENT DATED March 9, 2007
(To Prospectus Filed December 18, 2006)

3.00% Convertible Senior Subordinated Notes Due 2011

1,762,519 Common Shares

This prospectus supplement, together with the prospectus described above, is to be used by certain holders of the securities referenced above, or by their transferees, pledgees, donees or their successors, in connection with the offer and sale of the securities. This prospectus supplement should be read in conjunction with the prospectus and is qualified by reference to the prospectus, except to the extent that the information contained in this prospectus supplement supersedes the information contained in the prospectus.

The table included in the section captioned “Selling Security Holders” commencing on page 19 of the prospectus is hereby amended to add the selling security holder identified below and to reflect the notes, and common stock issuable upon conversion of the notes, for such selling security holder, as shown below:

														No. of Shares				No. of				No. of Shares
		Amount of												of Common				Shares of				of Common
		Notes				% of Notes				Amount of Notes				Stock				Common				Stock Owned
		Beneficially				Beneficially				Being Offered				Beneficially				Stock Being				After
Name of Selling Stockholder		Owned ($)				Owned				($) (a)				Owned(b)(c)				Offered (a)(c)				Offering (a)
Deutsche Bank Securities Inc. (d)(e)		$	10,000,000				9.1	%		$	10,000,000				160,229				160,229				0
Daimler Chrysler Corp Emp. #1 Retirement Plan, dtd 4/1/89 (e)(f)			3,571,000				3.2	%			53,571,000				57,2185				57,218				0
FPL Group Employee Pension Plan (e)(f)			1,309,000				1.2	%			1,309,000				20,974				20,974				0
Franklin and Marshall College (e)(f)			84,000				*				84,000				1,346				1,346				0
Rampart Enhanced Convertible Investors, LLC (e)(f)			636,000				*				636,000				10,191				10,191				0

*

Less than 1%

(a)

Because the selling security holder may sell pursuant to the prospectus all or a portion of the offered notes, and common stock issuable upon conversion of the notes, we cannot know or estimate number or percentage of notes and common stock that the selling security holder will hold upon the termination of any particular offering. Please refer to the “Plan of Distribution” beginning on page 54 of the prospectus. The information presented assumes that the selling security holder will fully convert the notes for cash and shares of our common stock, and that the

		selling security holder will sell all shares of our common stock that it receives pursuant to such conversion.
(b)		Includes shares of our common stock issuable upon conversion of the notes.
(c)		The number of shares of our common stock issuable upon conversion of the notes is calculated to be the maximum number of shares issuable upon conversion assuming (i) the value of the notes approach an infinite amount at the time of conversion, with the $110,000,000 principal amount paid in cash and the remaining value paid in shares of our common stock, and (ii) the conversion of the full amount of notes held by the selling security holders at the initial conversion price of $62.41, which corresponds to the initial conversion rate of 16.0229 shares per $1,000 principal amount of the notes. Accordingly, the number of shares of our common stock to be offered using this prospectus may be less than the amount shown. Fractional shares will not be issued upon conversion of the notes. Instead, we will pay cash in lieu of fractional shares, if any. Due to the effects of rounding, the numbers shown in this column do not equal exactly 16.0229 shares per $1,000 principal amount of the notes.
(d)		This selling security holder has identified itself as a registered broker-dealer and, accordingly, it is deemed to be, under the interpretations of the SEC, an “underwriter” within the meaning of the Securities Act. Deutsche bank Securities Inc. is a wholly owned subsidiary of Deutsche Bank Corporation, which is a publicly owned corporation.
(e)		This selling security holder has indicated that to its knowledge it does not own any shares of our common stock other than shares issuable upon conversion of the notes. For purposes of this table, we have assumed that it does not.
(f)		Each of DaimlerChrysler Corp Emp. #1 Retirement Plan, dtd 4/1/89, Franklin and Marshall College, FPL Group Employee Pension Plan and Rampart Enhanced Convertible Investors, LLC has indicated that Jack Feiler, Chief Investment Officer of Palisade Capital Management, LLC, investment advisor to such selling security holder, exercises sole or shared voting or investment power over the notes and the common stock issuable upon the conversion of the notes held by it.

The foregoing table is based solely on the most current information provided to us by the selling security holders named above. None of these selling security holders has, within the past three years, held any position or office with us or any of our predecessors or affiliates, or had any other material relationship with us or any of our predecessors or affiliates.