Quarterly report pursuant to Section 13 or 15(d)

Marketable Securities - Additional Information (Detail)

v3.3.1.900
Marketable Securities - Additional Information (Detail) - USD ($)
 3 Months Ended 6 Months Ended
Oct. 31, 2015
Oct. 31, 2014
Oct. 31, 2015
Oct. 31, 2014
Apr. 30, 2015
Schedule Of Marketable Securities [Line Items]          
Proceeds from maturities of available-for-sale securities $ 8,100,000 $ 0 $ 11,100,000 $ 2,000,000  
Trading securities [1],[2] 144,905,000   144,905,000   $ 131,399,000
Gross unrealized gains 5,300,000   5,300,000   8,300,000
Gross unrealized losses $ 900,000   $ 900,000   $ 200,000
Minimum          
Schedule Of Marketable Securities [Line Items]          
Available-for-sale marketable securities, remaining maturities     1 month    
Maximum          
Schedule Of Marketable Securities [Line Items]          
Available-for-sale marketable securities, remaining maturities     2 months    
[1] The Company's financial assets measured at fair value on a recurring basis include trading securities classified as Level 1 and available-for-sale securities classified as Level 2. As of October 31, 2015 and April 30, 2015, the Company had no investments classified as Level 3.
[2] These investments are held in trust for settlement of the Company's vested and unvested obligations of $140.9 million and $129.1 million as of October 31, 2015 and April 30, 2015, respectively, under the ECAP (see Note 6 - Deferred Compensation and Retirement Plans). During the three and six months ended October 31, 2015, the fair value of the investments decreased; therefore, the Company recognized a loss of $2.5 million and $1.8 million, respectively, which was recorded in other (loss) income, net. During the three and six months ended October 31, 2014, the fair value of the investments increased; therefore, the Company recognized income of $2.5 million and $4.5 million, respectively, which was recorded in other (loss) income, net.