Summary of Marketable Securities (Parenthetical) (Detail) - USD ($) $ in Thousands	12 Months Ended
Apr. 30, 2016	Apr. 30, 2015	Apr. 30, 2014
Schedule Of Marketable Securities [Line Items]
Obligations for which assets are held in trust	$ 138,800	$ 129,100
Gain (loss) on marketable securities	$ (3,333)	$ 8,829	$ 9,498

- Definition

This item represents the net total realized and unrealized gain (loss) included in earnings for the period as a result of selling or holding marketable securities categorized as trading, available-for-sale, or held-to-maturity, including the unrealized holding gain (loss) of held-to-maturity securities transferred to the trading security category and the cumulative unrealized gain (loss) which was included in other comprehensive income (a separate component of shareholders' equity) for available-for-sale securities transferred to trading securities during the period.

+ References + Details