Domestic and Foreign Components of Income (Loss) From Continuing Operations Before Domestic and Foreign Income and Other Taxes And Equity in Earnings of Unconsolidated Subsidiaries (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Apr. 30, 2013	Apr. 30, 2012	Apr. 30, 2011
Income Taxes [Line Items]
Domestic	$ 15,915	$ 42,375	$ 56,741
Foreign	31,905	38,429	32,963
Income before provision for income taxes and equity in earnings of unconsolidated subsidiaries	$ 47,820	$ 80,804	$ 89,704

Domestic and Foreign Components of Income (Loss) From Continuing Operations Before Domestic and Foreign Income and Other Taxes And Equity in Earnings of Unconsolidated Subsidiaries (Detail) (USD $)
In Thousands, unless otherwise specified

12 Months Ended

Apr. 30, 2013

Apr. 30, 2012

Apr. 30, 2011

Income Taxes [Line Items]

Domestic

$ 15,915

$ 42,375

$ 56,741

Foreign

31,905

38,429

32,963

Income before provision for income taxes and equity in earnings of unconsolidated subsidiaries

$ 47,820

$ 80,804

$ 89,704