Debt (Details Textual) (USD $) In Millions, except Share data, unless otherwise specified		3 Months Ended		1 Months Ended	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2012 Convertible subordinated notes [Member]	Dec. 31, 2011 Convertible subordinated notes [Member]	Feb. 28, 2011 TILC warehouse facility [Member]	Mar. 31, 2012 TILC warehouse facility [Member] Installment	Mar. 31, 2012 Corporate Revolving Credit Facility [Member]
Debt (Textual) [Abstract]
Revolving credit facility					$ 475.0	$ 425.0
Revolving credit facility expiration date before extended	Oct. 20, 2016
Used revolving credit facility for letter of credit						72.6
Availability of the revolving credit facility					192.3	352.4
Borrowing under revolving credit facility exclusive of letters of credit	0
Letter of credit maturing current year	0.4
Amended credit facility, description of variable rate reference rate basis						LIBOR
Percentage points added to LIBOR to compute Interest rates on the amended credit facility						1.50%
Amended credit facility, description of variable rate reference rate basis, alternative computation						prime
Percentage points added to prime to compute Interest rates on the amended credit facility, alternative computation						0.50%
Interest rate on notes		3.875%
Date before which notes can't be redeemed	Jun. 01, 2018
Capital in excess of par value related to the convertible subordinated notes' conversion options		92.8	92.8
Effective annual interest rate based upon the estimated market interest rate		8.42%
Conversion price of convertible subordinated notes		$ 51.36
Number of shares issuable in exchange of Convertible Subordinated Notes		8,761,682
TILC warehouse facility					$ 282.7
Interest at a defined index rate plus a margin for advances under the facility					2.25%
Additional period for warehouse loan facility				2 years
Maturity date of warehouse loan facility					February, 2013
Number of installments payable for amounts outstanding at maturity, absent renewal					3
Installment payable date, installment one					August 2013
Installment payable date, installment two					February 2014
Installment payable date, installment three					August 2014