Supplementary Financial Information (Details) (USD $)	3 Months Ended												12 Months Ended
	Apr. 30, 2012	Jan. 31, 2012		Oct. 31, 2011	Jul. 31, 2011		Apr. 30, 2011	Jan. 31, 2011		Oct. 31, 2010	Jul. 31, 2010		Apr. 30, 2012	Apr. 30, 2011	Apr. 30, 2010
Supplementary Financial Information [Abstract]
Revenue	$ 454,500,000	$ 451,100,000		$ 447,000,000	$ 430,100,000		$ 445,000,000	$ 447,900,000		$ 441,800,000	$ 407,900,000		$ 1,782,742,000	$ 1,742,551,000	$ 1,699,062,000
Gross profit	315,600,000	309,000,000		314,300,000	300,400,000		308,600,000	309,900,000		302,300,000	282,700,000		1,239,300,000	1,203,500,000
Operating income	69,700,000	78,500,000	[1]	72,000,000	60,200,000		37,600,000	69,700,000	[1]	77,700,000	63,100,000		280,419,000	248,148,000	242,592,000
Net income	48,200,000	62,900,000	[1],[2]	50,800,000	50,800,000	[3]	28,600,000	45,600,000	[1],[2]	53,700,000	44,000,000	[3]	212,746,000	171,889,000	143,543,000
Income per share [Abstract]
Diluted (in dollars per share)	$ 0.80	$ 1.03	[1],[2]	$ 0.83	$ 0.82	[3]	$ 0.46	$ 0.74	[1],[2]	$ 0.88	$ 0.72	[3]	$ 3.47	$ 2.80	$ 2.41
Basic (in dollars per share)	$ 0.81	$ 1.05	[1],[2]	$ 0.84	$ 0.84	[3]	$ 0.47	$ 0.76	[1],[2]	$ 0.89	$ 0.74	[3]	$ 3.53	$ 2.86	$ 2.45
Non-cash deferred tax benefit associated with new tax legislation enacted in the U.K.					(8,800,000)						(4,200,000)		(8,769,000)	(4,155,000)	0
Non-cash deferred tax benefit associated with new tax legislation enacted in the U.K. (in dollars per diluted share)					$ 0.14						$ 0.07
Corporate income tax rate, U.K. (in hundredths)					2.00%						1.00%		2.00%	1.00%
Other Tax Expense (Benefit)		7,500,000
Reversal of an income tax reserve recorded in conjunction with the Blackwell acquisition		$ 0.12
Pre-tax bad debt provision related to Borders Group, Inc.								9,300,000					0	9,290,000	0
After tax bad debt provision related to Borders Group, Inc.											$ 6,000,000
Pre-tax bad debt provision related to Borders Group, Inc. (in dollars per diluted share)								$ 0.10

[1] In the third quarter of fiscal year 2011, the Company recorded a $9.3 million bad debt provision ($6.0 million after taxes), or $0.10 per diluted share, related to the Company's customer, Borders Group, Inc. ("Borders"). On February 16, 2011, Borders filed a petition for reorganization relief under Chapter 11 of the U.S. Bankruptcy code.

[2] In the third quarter of fiscal year 2012, the Company recorded a $7.5 million tax benefit, or $0.12 per diluted share, related to the reversal of an income tax reserve recorded in conjunction with the Blackwell acquisition in fiscal year 2007.

[3] In the first quarters of fiscal years 2012 and 2011, the Company recorded non-cash deferred tax benefits of $8.8 million, or $0.14 per diluted share, and $4.2 million, or $0.07 per diluted share, respectively, principally associated with new tax legislation enacted in the U.K. that reduced the U.K. statutory income tax rates by 2% and 1%, respectively. The benefits recognized by the Company reflect the remeasurement of all applicable U.K. deferred tax balances to the new income tax rates as of April 1, 2012 and 2011, respectively.