Amortizable Intangible Assets and Unamortizable Intangible Assets (Detail) - USD ($) $ in Thousands	9 Months Ended
	Jan. 27, 2018	Jan. 28, 2017	Apr. 29, 2017
Intangible Assets by Major Class [Line Items]
Gross Carrying Amount	$ 17,234	$ 25,453
Accumulated Amortization	(16,771)	(24,378)
Total	463	1,075
Unamortizable intangible assets	309,294	309,294
Total amortizable and unamortizable, intangible assets	309,757	310,369	$ 310,205
Trade name
Intangible Assets by Major Class [Line Items]
Unamortizable intangible assets	293,400	293,400
Publishing contracts
Intangible Assets by Major Class [Line Items]
Unamortizable intangible assets	15,894	15,894
Technology
Intangible Assets by Major Class [Line Items]
Gross Carrying Amount	10,710	10,710
Accumulated Amortization	(10,303)	(9,895)
Total	$ 407	$ 815
Technology | Minimum
Intangible Assets by Major Class [Line Items]
Useful Life	5 years	5 years
Technology | Maximum
Intangible Assets by Major Class [Line Items]
Useful Life	10 years	10 years
Distribution contracts
Intangible Assets by Major Class [Line Items]
Useful Life		10 years
Gross Carrying Amount		$ 8,325
Accumulated Amortization		(8,127)
Total		198
Other
Intangible Assets by Major Class [Line Items]
Gross Carrying Amount	$ 6,524	6,418
Accumulated Amortization	(6,468)	(6,356)
Total	$ 56	$ 62
Other | Minimum
Intangible Assets by Major Class [Line Items]
Useful Life	3 years	3 years
Other | Maximum
Intangible Assets by Major Class [Line Items]
Useful Life	10 years	10 years