Long-term Debt and Other Credit Arrangements - Additional Information (Detail) (USD $)	0 Months Ended	12 Months Ended				12 Months Ended			12 Months Ended			0 Months Ended	12 Months Ended			0 Months Ended	12 Months Ended		12 Months Ended
	May 06, 2013	Apr. 30, 2014	Apr. 30, 2013	Apr. 30, 2014 Standby Letters of Credit [Member]	Aug. 10, 2014 Scenario, Forecast [Member]	Apr. 30, 2014 London Interbank Offered Rate (LIBOR) [Member]	Jun. 10, 2014 Subsequent Event [Member]	Jun. 10, 2014 Subsequent Event [Member] Maximum [Member]	Apr. 30, 2014 Unsecured Debt [Member]	Apr. 30, 2014 Unsecured Debt [Member] Minimum [Member]	Apr. 30, 2014 Unsecured Debt [Member] Maximum [Member]	May 06, 2013 Term Loan A [Member]	Apr. 30, 2014 Term Loan A [Member]	Apr. 30, 2014 Term Loan A [Member] August 1, 2017 [Member]	Apr. 30, 2014 Term Loan A [Member] September 1, 2017 [Member]	May 06, 2013 Term Loan B [Member]	Apr. 30, 2014 Term Loan B [Member]	Apr. 30, 2014 Term Loan B [Member] November 3, 2014 [Member]	Apr. 30, 2014 Line of Credit [Member]	Apr. 30, 2014 Secured Debt [Member]	Apr. 30, 2014 Revolving Credit Facilities [Member]	Apr. 30, 2014 Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Loan agreement	$ 20,000,000
Credit facility outstanding				4,300,000					15,000,000			3,450,000				1,550,000			2,900,000			6,700,000
Letters of credit	4,700,000				6,510,000		4,700,000	8,510,000
Credit facility expiration date	May 01, 2016								Jul. 31, 2014			May 01, 2020				May 01, 2020
Debt, variable interest rate						1.575%			1.575%	1.575%	2.175%						1.575%		1.50%
Periodic payments		17,000												17,000	79,000		18,000
Interest rate at period end									1.773%										1.75%
Interest rate description		The Line of Credit, and the borrowing rate at that date was 1.75%. Monthly interest payments under the Line of Credit were payable at the Daily One Month LIBOR interest rate plus 1.5% per annum.							Monthly interest payments under the facility are payable calculated at the 30-day LIBOR Market Interest Rate plus a variable rate
Term loan, Payment terms		The term loan required monthly principal payments of $17,000, plus interest calculated at the 30-day LIBOR Market Index Rate plus 1.575%, with payment of the outstanding principal balance and any unpaid interest at the term loan maturity date.											Payments are due under Term Loan A in consecutive equal monthly principal payments in the amount of $17,000 until August 1, 2017, and then in consecutive equal monthly principal payments in the amount of $79,000 each, commencing on September 1, 2017 and continuing on the first business day of each month thereafter until May 1, 2020, and at that time, all principal, accrued unpaid interest and other charges outstanding under Term Loan A shall be due and payable in full.				Payments in the amount of $18,000 until May 1, 2020, and at that time, all principal
Fixed rate percentage		4.875%											4.875%	4.37%			1.73%	3.07%
Principal payment for the year 2015																				421,000
Principal payment for the year 2016																				421,000
Principal payment for the year 2017																				421,000
Principal payment for the year 2018																				915,000
Principal payment for the year 2019																				1,164,000
Principal payment for the year 2020																				1,271,000
Unused and available credit facility																					12,800,000
Bank Guarantees outstanding to customers		1,784,000	576,000
Letter of credit		2,100,000
Secured long term debt		$ 4,000,000