Segment Information (Detail) - Schedule of segment reporting information (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended
	Nov. 30, 2012		Nov. 30, 2011		Nov. 30, 2012		Nov. 30, 2011		May 31, 2012	May 31, 2011
Revenues	$ 616.2		$ 685.3		$ 909.8		$ 1,003.3
Bad debt expense	4.0		3.3		4.5		4.7
Depreciation and amortization	16.7	[1]	15.5	[1]	32.8	[1]	30.6	[1]
Amortization	12.0	[2]	12.5	[2]	23.8	[2]	24.4	[2]
Loss on leases			6.2				6.2
Segment operating income (loss)	100.9		140.0		53.4		106.8
Segment assets	1,762.0		1,601.6		1,762.0		1,601.6
Goodwill	157.8		155.1		157.8		155.1		157.7	154.2
Expenditures for long-lived assets including royalty advances	38.3		33.3		75.3		57.3
Long-lived assets	697.0		687.7		697.0		687.7
Children's Book Publishing and Distribution [Member]
Revenues	350.1	[3],[4]	393.0	[3],[4]	421.2	[3],[4]	470.5	[3],[4]
Bad debt expense	1.8	[3],[4]	1.6	[3],[4]	1.6	[3],[4]	1.6	[3],[4]
Depreciation and amortization	4.3	[1],[3],[4]	3.8	[1],[3],[4]	8.1	[1],[3],[4]	7.5	[1],[3],[4]
Amortization	3.8	[2],[3],[4]	3.1	[2],[3],[4]	7.3	[2],[3],[4]	6.2	[2],[3],[4]
Loss on leases				[3],[4]		[3],[4]		[3],[4]
Segment operating income (loss)	68.9	[3],[4]	108.7	[3],[4]	13.7	[3],[4]	58.5	[3],[4]
Segment assets	564.4	[3],[4]	541.4	[3],[4]	564.4	[3],[4]	541.4	[3],[4]
Goodwill	54.3	[3],[4]	54.3	[3],[4]	54.3	[3],[4]	54.3	[3],[4]
Expenditures for long-lived assets including royalty advances	12.1	[3],[4]	12.9	[3],[4]	27.2	[3],[4]	21.1	[3],[4]
Long-lived assets	171.4	[3],[4]	175.6	[3],[4]	171.4	[3],[4]	175.6	[3],[4]
Educational Technology and Services [Member]
Revenues	52.2	[3]	65.4	[3]	132.2	[3]	162.0	[3]
Bad debt expense	(0.2)	[3]	0.4	[3]	0.1	[3]	0.7	[3]
Depreciation and amortization	0.3	[1],[3]	0.4	[1],[3]	0.6	[1],[3]	0.7	[1],[3]
Amortization	5.2	[2],[3]	5.1	[2],[3]	10.7	[2],[3]	10.3	[2],[3]
Loss on leases				[3]		[3]		[3]
Segment operating income (loss)	5.3	[3]	14.6	[3]	30.1	[3]	53.4	[3]
Segment assets	170.9	[3]	157.6	[3]	170.9	[3]	157.6	[3]
Goodwill	22.7	[3]	22.7	[3]	22.7	[3]	22.7	[3]
Expenditures for long-lived assets including royalty advances	9.2	[3]	6.0	[3]	17.4	[3]	11.3	[3]
Long-lived assets	106.9	[3]	98.6	[3]	106.9	[3]	98.6	[3]
Classroom Supplemental Materials Publishing [Member]
Revenues	53.2	[3],[5]	58.7	[3],[5]	91.1	[3],[5]	104.4	[3],[5]
Bad debt expense	1.4	[3],[5]	0.5	[3],[5]	1.2	[3],[5]	0.9	[3],[5]
Depreciation and amortization	0.3	[1],[3],[5]	0.2	[1],[3],[5]	0.7	[1],[3],[5]	0.5	[1],[3],[5]
Amortization	1.9	[2],[3],[5]	1.7	[2],[3],[5]	3.6	[2],[3],[5]	3.1	[2],[3],[5]
Loss on leases				[3],[5]		[3],[5]		[3],[5]
Segment operating income (loss)	7.4	[3],[5]	10.3	[3],[5]	4.8	[3],[5]	12.4	[3],[5]
Segment assets	170.2	[3],[5]	158.8	[3],[5]	170.2	[3],[5]	158.8	[3],[5]
Goodwill	65.4	[3],[5]	64.0	[3],[5]	65.4	[3],[5]	64.0	[3],[5]
Expenditures for long-lived assets including royalty advances	2.4	[3],[5]	3.1	[3],[5]	4.2	[3],[5]	4.4	[3],[5]
Long-lived assets	90.0	[3],[5]	81.0	[3],[5]	90.0	[3],[5]	81.0	[3],[5]
Media, Licensing and Advertising [Member]
Revenues	17.0	[3],[4]	24.1	[3],[4]	31.4	[3],[4]	34.6	[3],[4]
Bad debt expense		[3],[4]		[3],[4]		[3],[4]		[3],[4]
Depreciation and amortization	0.1	[1],[3],[4]	0.3	[1],[3],[4]	0.2	[1],[3],[4]	0.4	[1],[3],[4]
Amortization	0.8	[2],[3],[4]	2.1	[2],[3],[4]	1.3	[2],[3],[4]	3.6	[2],[3],[4]
Loss on leases				[3],[4]		[3],[4]		[3],[4]
Segment operating income (loss)	1.4	[3],[4]	2.5	[3],[4]	1.4	[3],[4]	(2.1)	[3],[4]
Segment assets	32.3	[3],[4]	44.2	[3],[4]	32.3	[3],[4]	44.2	[3],[4]
Goodwill	5.4	[3],[4]	5.4	[3],[4]	5.4	[3],[4]	5.4	[3],[4]
Expenditures for long-lived assets including royalty advances	1.1	[3],[4]	2.1	[3],[4]	3.1	[3],[4]	4.0	[3],[4]
Long-lived assets	13.2	[3],[4]	20.2	[3],[4]	13.2	[3],[4]	20.2	[3],[4]
Overhead [Member]
Revenues		[3],[6]		[3],[6]		[3],[6]		[3],[6]
Bad debt expense		[3],[6]		[3],[6]		[3],[6]		[3],[6]
Depreciation and amortization	10.4	[1],[3],[6]	9.4	[1],[3],[6]	20.7	[1],[3],[6]	18.6	[1],[3],[6]
Amortization		[2],[3],[6]		[2],[3],[6]		[2],[3],[6]		[2],[3],[6]
Loss on leases			6.2	[3],[6]		[3],[6]	6.2	[3],[6]
Segment operating income (loss)	(6.8)	[3],[6]	(22.7)	[3],[6]	(24.1)	[3],[6]	(41.9)	[3],[6]
Segment assets	513.9	[3],[6]	419.5	[3],[6]	513.9	[3],[6]	419.5	[3],[6]
Goodwill		[3],[6]		[3],[6]		[3],[6]		[3],[6]
Expenditures for long-lived assets including royalty advances	10.8	[3],[6]	7.6	[3],[6]	18.3	[3],[6]	12.6	[3],[6]
Long-lived assets	244.3	[3],[6]	242.4	[3],[6]	244.3	[3],[6]	242.4	[3],[6]
Total Domestic [Member]
Revenues	472.5		541.2		675.9		771.5
Bad debt expense	3.0		2.5		2.9		3.2
Depreciation and amortization	15.4	[1]	14.1	[1]	30.3	[1]	27.7	[1]
Amortization	11.7	[2]	12.0	[2]	22.9	[2]	23.2	[2]
Loss on leases			6.2				6.2
Segment operating income (loss)	76.2		113.4		25.9		80.3
Segment assets	1,451.7		1,321.5		1,451.7		1,321.5
Goodwill	147.8		146.4		147.8		146.4
Expenditures for long-lived assets including royalty advances	35.6		31.7		70.2		53.4
Long-lived assets	625.8		617.8		625.8		617.8
International Segment [Member]
Revenues	143.7	[3],[7]	144.1	[3],[7]	233.9	[3],[7]	231.8	[3],[7]
Bad debt expense	1.0	[3],[7]	0.8	[3],[7]	1.6	[3],[7]	1.5	[3],[7]
Depreciation and amortization	1.3	[1],[3],[7]	1.4	[1],[3],[7]	2.5	[1],[3],[7]	2.9	[1],[3],[7]
Amortization	0.3	[2],[3],[7]	0.5	[2],[3],[7]	0.9	[2],[3],[7]	1.2	[2],[3],[7]
Loss on leases				[3],[7]		[3],[7]		[3],[7]
Segment operating income (loss)	24.7	[3],[7]	26.6	[3],[7]	27.5	[3],[7]	26.5	[3],[7]
Segment assets	310.3	[3],[7]	280.1	[3],[7]	310.3	[3],[7]	280.1	[3],[7]
Goodwill	10.0	[3],[7]	8.7	[3],[7]	10.0	[3],[7]	8.7	[3],[7]
Expenditures for long-lived assets including royalty advances	2.7	[3],[7]	1.6	[3],[7]	5.1	[3],[7]	3.9	[3],[7]
Long-lived assets	$ 71.2	[3],[7]	$ 69.9	[3],[7]	$ 71.2	[3],[7]	$ 69.9	[3],[7]

[1] Includes depreciation of property, plant and equipment and amortization of intangible assets.

[2] Includes amortization of prepublication and production costs.

[3] As discussed under "Discontinued Operations" in Note 1, "Basis of Presentation," the Company closed or sold several operations during fiscal 2009, fiscal 2010 and fiscal 2012, and presently holds for sale one facility. All of these businesses are classified as discontinued operations in the Company's financial statements and, as such, are not reflected in this table.

[4] As discussed under "Segment" in Note 1, a business previously reported in the Media, Licensing and Advertising segment is now included in the Children's Book Publishing and Distribution segment.

[5] Includes assets and results of operations acquired in a business acquisition as of February 8, 2012.

[6] Overhead includes all domestic corporate amounts not allocated to segments, including expenses and costs related to the management of corporate assets. Unallocated assets are principally comprised of deferred income taxes and property, plant and equipment related to the Company's headquarters in the metropolitan New York area, its fulfillment and distribution facilities located in Missouri and its facility located in Connecticut.

[7] Includes assets and results of operations acquired in a business acquisition as of January 3, 2012.