Long-Term Debt (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Apr. 30, 2012 Year	Apr. 30, 2011
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	$ 50
Line of credit facility, expiration date	March 14, 2014
Company's extensions period subject to lender consent (in years)	1
Facility secured by equity interest in first tier foreign subsidiaries	65.00%
Unrestricted cash and/or marketable securities	30
Interest rate description	Borrowings under the Facility bear interest, at the election of the Company, at the London Interbank Offered Rate (“LIBOR”) plus applicable margin or the base rate plus applicable margin. The base rate is the highest of (i) the published prime rate, (ii) the federal funds rate plus 0.50%, or (iii) one month LIBOR plus 2.0%. The applicable margin is based on a percentage per annum determined in accordance with a specified pricing grid based on (a) the total funded debt ratio of the Company and (b) with respect to LIBOR loans, whether such LIBOR loans are cash collateralized. For cash collateralized LIBOR loans, the applicable margin will range from 0.65% to 3.15% per annum. For LIBOR loans that are not cash collateralized and for based rate loans, the applicable margin will range from 1.50% to 4.50% per annum (if using LIBOR) and from 1.50% to 4.75% per annum (if using base rate).
Covenant description	The Facility is secured by substantially all of the assets of the Company’s domestic subsidiaries and 65% of the equity interest in all the first tier foreign subsidiaries. The financial covenants include a maximum consolidated leverage ratio, a minimum consolidated fixed charge coverage ratio and a minimum $30 million in unrestricted cash and/or marketable securities after taking into account the accrual for employee compensation and benefits.
Collateral for standby letters of credit	10.0
Standby letters of credit issued	2.9	2.9
Outstanding policy loans	73.3	72.9
Outstanding borrowings	0	0
Letters Of Credit [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	10
Csv of Coli Contracts [Member]
Debt Instrument [Line Items]
Outstanding policy loans	$ 73.3	$ 72.9
Federal Funds Rate [Member]
Debt Instrument [Line Items]
Margin for non cash collateral	0.50%
One Month LIBOR [Member]
Debt Instrument [Line Items]
Margin for non cash collateral	2.00%
Maximum [Member]
Debt Instrument [Line Items]
Quarterly commitment fees	0.50%
Maximum [Member] | Cash Collateralized Libor Loan [Member]
Debt Instrument [Line Items]
Margin for non cash collateral	3.15%
Maximum [Member] | Csv of Coli Contracts [Member]
Debt Instrument [Line Items]
Interest payable fixed and variable rates	8.00%
Maximum [Member] | LIBOR [Member] | Uncollateralized Libor Loan [Member]
Debt Instrument [Line Items]
Margin for non cash collateral	4.50%
Maximum [Member] | Base Rate [Member] | Uncollateralized Libor Loan [Member]
Debt Instrument [Line Items]
Margin for non cash collateral	4.75%
Minimum [Member]
Debt Instrument [Line Items]
Quarterly commitment fees	0.25%
Minimum [Member] | Cash Collateralized Libor Loan [Member]
Debt Instrument [Line Items]
Margin for non cash collateral	0.65%
Minimum [Member] | Csv of Coli Contracts [Member]
Debt Instrument [Line Items]
Interest payable fixed and variable rates	4.76%
Minimum [Member] | LIBOR [Member] | Uncollateralized Libor Loan [Member]
Debt Instrument [Line Items]
Margin for non cash collateral	1.50%
Minimum [Member] | Base Rate [Member] | Uncollateralized Libor Loan [Member]
Debt Instrument [Line Items]
Margin for non cash collateral	1.50%