Segment Information (Details) - Schedule of segment reporting information (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended
	Nov. 30, 2013		Nov. 30, 2012		Nov. 30, 2013		Nov. 30, 2012		May 31, 2013	May 31, 2012
Segment Reporting Information [Line Items]
Revenues	$ 623.2		$ 613.5		$ 899.5		$ 906.9
Bad debt expense	2.5		4.0		3.9		4.5
Depreciation and amortization	15.9	[1]	16.7	[1]	31.8	[1]	32.8	[1]
Amortization	14.6	[2]	12.0	[2]	27.9	[2]	23.8	[2]
Asset impairments	13.4	[3]			13.4	[3]
Segment operating income (loss)	94.7		102.0		48.8		55.0
Segment assets	1,579.5		1,760.7		1,579.5		1,760.7
Goodwill	144.5		157.8		144.5		157.8		157.9	157.7
Expenditures for long-lived assets including royalty advances	28.4		38.0		59.1		74.1
Long-lived assets	668.2		695.8		668.2		695.8
Children's Book Publishing and Distribution [Member]
Segment Reporting Information [Line Items]
Revenues	352.1	[4]	347.4	[4]	406.7	[4]	418.3	[4]
Bad debt expense	1.0	[4]	1.8	[4]	1.4	[4]	1.6	[4]
Depreciation and amortization	3.7	[1],[4]	4.3	[1],[4]	7.7	[1],[4]	8.1	[1],[4]
Amortization	4.1	[2],[4]	3.8	[2],[4]	8.1	[2],[4]	7.3	[2],[4]
Asset impairments	13.4	[3],[4]			13.4	[3],[4]
Segment operating income (loss)	68.9	[4]	69.4	[4]	7.4	[4]	14.5	[4]
Segment assets	489.6	[4]	565.3	[4]	489.6	[4]	565.3	[4]
Goodwill	40.9	[4]	54.3	[4]	40.9	[4]	54.3	[4]
Expenditures for long-lived assets including royalty advances	10.5	[4]	12.1	[4]	21.9	[4]	27.2	[4]
Long-lived assets	149.6	[4]	171.4	[4]	149.6	[4]	171.4	[4]
Educational Technology and Services [Member]
Segment Reporting Information [Line Items]
Revenues	60.9	[4]	52.2	[4]	155.7	[4]	132.2	[4]
Bad debt expense	0	[4]	(0.2)	[4]	0.4	[4]	0.1	[4]
Depreciation and amortization	0.2	[1],[4]	0.3	[1],[4]	0.5	[1],[4]	0.6	[1],[4]
Amortization	7.4	[2],[4]	5.2	[2],[4]	13.4	[2],[4]	10.7	[2],[4]
Asset impairments		[3],[4]				[3],[4]
Segment operating income (loss)	6.9	[4]	5.3	[4]	43.1	[4]	30.1	[4]
Segment assets	180.3	[4]	170.9	[4]	180.3	[4]	170.9	[4]
Goodwill	22.7	[4]	22.7	[4]	22.7	[4]	22.7	[4]
Expenditures for long-lived assets including royalty advances	7.3	[4]	9.2	[4]	15.8	[4]	17.4	[4]
Long-lived assets	118.2	[4]	106.9	[4]	118.2	[4]	106.9	[4]
Classroom and Supplemental Materials Publishing [Member]
Segment Reporting Information [Line Items]
Revenues	59.1	[4]	53.2	[4]	96.9	[4]	91.1	[4]
Bad debt expense	0.6	[4]	1.4	[4]	0.6	[4]	1.2	[4]
Depreciation and amortization	0.3	[1],[4]	0.3	[1],[4]	0.6	[1],[4]	0.7	[1],[4]
Amortization	2.2	[2],[4]	1.9	[2],[4]	4.5	[2],[4]	3.6	[2],[4]
Asset impairments		[3],[4]				[3],[4]
Segment operating income (loss)	10.7	[4]	7.4	[4]	9.1	[4]	4.8	[4]
Segment assets	152.8	[4]	170.2	[4]	152.8	[4]	170.2	[4]
Goodwill	65.4	[4]	65.4	[4]	65.4	[4]	65.4	[4]
Expenditures for long-lived assets including royalty advances	2.6	[4]	2.4	[4]	4.6	[4]	4.2	[4]
Long-lived assets	90.3	[4]	90.0	[4]	90.3	[4]	90.0	[4]
Media, Licensing and Advertising [Member]
Segment Reporting Information [Line Items]
Revenues	15.5	[4]	17.0	[4]	25.9	[4]	31.4	[4]
Bad debt expense	0.1	[4]		[4]	0.1	[4]		[4]
Depreciation and amortization	0	[1],[4]	0.1	[1],[4]	0.1	[1],[4]	0.2	[1],[4]
Amortization	0.5	[2],[4]	0.8	[2],[4]	1.0	[2],[4]	1.3	[2],[4]
Asset impairments		[3],[4]				[3],[4]
Segment operating income (loss)	(0.4)	[4]	2.0	[4]	(2.3)	[4]	2.2	[4]
Segment assets	27.1	[4]	31.0	[4]	27.1	[4]	31.0	[4]
Goodwill	5.4	[4]	5.4	[4]	5.4	[4]	5.4	[4]
Expenditures for long-lived assets including royalty advances	2.5	[4]	0.8	[4]	3.6	[4]	1.9	[4]
Long-lived assets	14.1	[4]	12.0	[4]	14.1	[4]	12.0	[4]
Overhead [Member]
Segment Reporting Information [Line Items]
Revenues		[4],[5]		[4],[5]		[4],[5]		[4],[5]
Bad debt expense		[4],[5]		[4],[5]		[4],[5]		[4],[5]
Depreciation and amortization	10.5	[1],[4],[5]	10.4	[1],[4],[5]	20.5	[1],[4],[5]	20.7	[1],[4],[5]
Amortization		[2],[4],[5]		[2],[4],[5]		[2],[4],[5]		[2],[4],[5]
Asset impairments		[3],[4],[5]				[3],[4],[5]
Segment operating income (loss)	(13.6)	[4],[5]	(6.8)	[4],[5]	(30.0)	[4],[5]	(24.1)	[4],[5]
Segment assets	456.4	[4],[5]	513.0	[4],[5]	456.4	[4],[5]	513.0	[4],[5]
Goodwill		[4],[5]		[4],[5]		[4],[5]		[4],[5]
Expenditures for long-lived assets including royalty advances	2.8	[4],[5]	10.8	[4],[5]	8.0	[4],[5]	18.3	[4],[5]
Long-lived assets	228.7	[4],[5]	244.3	[4],[5]	228.7	[4],[5]	244.3	[4],[5]
Total Domestic [Member]
Segment Reporting Information [Line Items]
Revenues	487.6		469.8		685.2		673.0
Bad debt expense	1.7		3.0		2.5		2.9
Depreciation and amortization	14.7	[1]	15.4	[1]	29.4	[1]	30.3	[1]
Amortization	14.2	[2]	11.7	[2]	27.0	[2]	22.9	[2]
Asset impairments	13.4	[3]			13.4	[3]
Segment operating income (loss)	72.5		77.3		27.3		27.5
Segment assets	1,306.2		1,450.4		1,306.2		1,450.4
Goodwill	134.4		147.8		134.4		147.8
Expenditures for long-lived assets including royalty advances	25.7		35.3		53.9		69.0
Long-lived assets	600.9		624.6		600.9		624.6
International Segment [Member]
Segment Reporting Information [Line Items]
Revenues	135.6	[4]	143.7	[4]	214.3	[4]	233.9	[4]
Bad debt expense	0.8	[4]	1.0	[4]	1.4	[4]	1.6	[4]
Depreciation and amortization	1.2	[1],[4]	1.3	[1],[4]	2.4	[1],[4]	2.5	[1],[4]
Amortization	0.4	[2],[4]	0.3	[2],[4]	0.9	[2],[4]	0.9	[2],[4]
Asset impairments		[3],[4]				[3],[4]
Segment operating income (loss)	22.2	[4]	24.7	[4]	21.5	[4]	27.5	[4]
Segment assets	273.3	[4]	310.3	[4]	273.3	[4]	310.3	[4]
Goodwill	10.1	[4]	10.0	[4]	10.1	[4]	10.0	[4]
Expenditures for long-lived assets including royalty advances	2.7	[4]	2.7	[4]	5.2	[4]	5.1	[4]
Long-lived assets	$ 67.3	[4]	$ 71.2	[4]	$ 67.3	[4]	$ 71.2	[4]

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

[2] Includes amortization of prepublication and production costs.

[3] Includes an impairment of goodwill (see Note 7, "Goodwill and Other Intangibles").

[4] As discussed under "Discontinued Operations" in Note 1, "Basis of Presentation," the Company closed several operations during fiscal 2012 and fiscal 2013. All of these businesses are classified as discontinued operations in the Company's financial statements and, as such, are not reflected in this table.

[5] 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. Overhead also includes amounts previously allocated to the Children's Book Publishing and Distribution segment for the computer club business that was discontinued in the fourth quarter of fiscal 2013.