Common Shares and Stock-Based Compensation - Additional Information (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended																					12 Months Ended				12 Months Ended
	Feb. 28, 2013	Feb. 29, 2012	Feb. 28, 2011	Feb. 28, 2013 Minimum [Member]	Feb. 28, 2013 Maximum [Member]	Feb. 28, 2013 Stock Options [Member]	Feb. 29, 2012 Stock Options [Member]	Feb. 28, 2011 Stock Options [Member]	Feb. 28, 2013 Performance shares [Member]	Feb. 28, 2011 Performance shares [Member]	Feb. 28, 2010 Performance shares [Member]	Feb. 28, 2011 Performance shares [Member] Amended Plan [Member]	Feb. 28, 2010 Performance shares [Member] Amended Plan [Member]	Feb. 28, 2013 Restricted stock units [Member]	Feb. 29, 2012 Restricted stock units [Member]	Feb. 28, 2011 Restricted stock units [Member]	Feb. 28, 2013 Tranche 1 [Member]	Feb. 28, 2013 Tranche 2 [Member]	Feb. 28, 2013 Tranche 3 [Member]	Feb. 28, 2013 Common shares Class A [Member]	Feb. 29, 2012 Common shares Class A [Member]	Feb. 28, 2013 Common shares Class A [Member] Restricted stock units [Member]	Feb. 28, 2013 Common shares Class A [Member] Tranche 1 [Member]	Feb. 28, 2013 Common shares Class B [Member]	Feb. 29, 2012 Common shares Class B [Member]	Feb. 28, 2013 Common shares Class B [Member] Restricted stock units [Member]	Feb. 28, 2013 Common shares Class B [Member] Tranche 1 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares authorized																				187,600,000	187,600,000			15,832,968	15,832,968
Number of voting right per share																				One vote per share				Ten votes per share
Period of commencement of option exercisable						Twelve months after the date of grant
Period of expiration of stock option						Not more than ten years
Weighted average fair value per share of options granted						$ 0.00	$ 0.00	$ 10.43
Number of performance shares initially granted																				684,810			222,996	359,496			114,800
Performance shares granted																	March 1, 2012 to February 28, 2013	March 1, 2012 to February 28, 2014	March 1, 2012 to February 28, 2015	Equally divided into three separate tranches				Equally divided into three separate tranches
Percentage of performance achievement				0.00%	200.00%
Period required for the shares to continuing service											Two years			Two or three years
Number of performance shares												746,000,000	709,000,000
Fair value per share of the performance and restricted shares									$ 12.72	$ 10.20				$ 14.93	$ 22.64	$ 23.65
Cost incurred on receiving common shares by employees																						$ 0				$ 0
Stock-based compensation	10,743	10,982	13,017
Period of unrecognized compensation expense, recognized	1 year 6 months
Unrecognized compensation expense, before taxes						25			8,887					2,901
Cash received from stock options exercised	1,259	13,310	18,842
Total intrinsic value of options exercised	7,423	17,117	16,666
Actual tax benefit realized from the exercise of stock-based payment arrangements	$ 2,929	$ 6,705	$ 6,510
Number of shares available for future grant																				436,714,000				0