Debt (Details Textual) (USD $) In Thousands, unless otherwise specified	1 Months Ended		12 Months Ended						12 Months Ended													3 Months Ended				3 Months Ended			3 Months Ended
	Feb. 29, 2012	Feb. 28, 2011	Feb. 29, 2012	Feb. 28, 2011	Feb. 28, 2010	Jun. 11, 2010 Amended and Restated Credit Agreement [Member]	Feb. 29, 2012 Accounts Receivable Facility [Member]	Sep. 21, 2011 Accounts Receivable Facility [Member]	Feb. 29, 2012 Accounts Receivable Facility [Member] Minimum [Member]	Feb. 29, 2012 Accounts Receivable Facility [Member] Maximum [Member]	Feb. 29, 2012 Credit Agreement [Member]	Jan. 18, 2012 Credit Agreement [Member]	Jun. 11, 2010 Credit Agreement [Member]	Jan. 18, 2012 Credit Agreement [Member] Minimum [Member]	Jun. 11, 2010 Credit Agreement [Member] Minimum [Member]	Jan. 18, 2012 Credit Agreement [Member] Maximum [Member]	Jun. 11, 2010 Credit Agreement [Member] Maximum [Member]	Feb. 29, 2012 Publicly Traded [Member]	Feb. 28, 2011 Publicly Traded [Member]	Feb. 29, 2012 7.375% senior notes, due 2021 [Member]	Nov. 30, 2011 7.375% senior notes, due 2021 [Member]	Feb. 29, 2012 7.375% senior notes, due 2016 [Member]	Feb. 28, 2011 7.375% senior notes, due 2016 [Member]	Feb. 24, 2009 7.375% senior notes, due 2016 [Member]	May 24, 2006 7.375% senior notes, due 2016 [Member]	Feb. 29, 2012 7.375% notes, due 2016 [Member]	Feb. 28, 2011 7.375% notes, due 2016 [Member]	Feb. 24, 2009 7.375% notes, due 2016 [Member]	Feb. 29, 2012 7.375% senior notes and notes, due 2016 [Member]	Feb. 29, 2012 6.10% senior notes, due 2028 [Member]	Feb. 28, 2011 6.10% senior notes, due 2028 [Member]	Feb. 29, 2012 Letters of Credit [Member]
Debt Instrument [Line Items]
Increase in size of the revolving credit facility						$ 350,000						$ 400,000	$ 350,000																			$ 121,828
Aggregate principal amount of senior unsecured notes																					225,000			22,000	200,000			32,686
Interest rate of debt																				7.375%				7.375%	7.375%			7.375%		6.10%
Repayment of long term debt under tender																						180,358				24,514
Cost charged on repayment of notes																													9,101
Discount from the issuance of unsecured notes	0	22,179	0	22,179
Debt instrument principal amount outstanding percentage																						81.00%				75.00%
Redeemed notes pursuant to tender offers																													49,814
Fair value of the traded debt	0	0	0	0														239,562	237,453
Quoted market prices of Corporation's publicly traded debt, carrying value	225,181	232,688	225,181	232,688														225,181	232,688	225,000			213,077				19,430			181	181
Line of credit facility potential maximum borrowing capacity												450,000	400,000
Percentage guaranteed on capital stock												65.00%
Percentage of principal amount on accrued but unpaid interest												100.00%
Available financing of receivables purchase agreement								70,000
Available financing of receivables purchase agreement								80,000
Amount that can be borrowed, repaid or re-borrowed under the revolving credit facility												400,000	350,000
Line of credit facility basis spread on libor rate														1.25%	2.25%	2.25%	3.50%
Decrease applicable margin leverage ratio of credit facility, Before Amendment														0.25%	1.25%	1.25%	2.50%
Unused portion of revolving credit facility														0.25%	0.375%	0.40%	0.50%
Remaining unamortized discount and deferred financing costs related to notes written off																													21,711
Federal fund rate							0.50%
Balances outstanding under the revolving credit facility																																31,791
Ability to increase credit agreement on revolving basis											50,000
Letters of credit outstanding							12,551				19,240
Annual commitment fee									0.30%	0.40%
Loss on extinguishment of debt			30,812																										30,812
Long and Short Term Debt (Textual) [Abstract]
Long-term debt net of unamortized discounts	0	22,179	0	22,179
Debt due within one year	0	0	0	0
Interest paid on debt			34,946	21,637	23,294
Balances outstanding under the amended and restated receivables purchase agreement	$ 0	$ 0
Line of credit facility borrowings period			5 years