Note 8 - Benefit Plans	12 Months Ended
Apr. 30, 2014
Disclosure Text Block Supplement [Abstract]
Compensation and Employee Benefit Plans [Text Block]	8. Benefit plans 401(k) plan The Company provides employees with a defined contribution 401(k) plan. The 401(k) plan covers all employees who meet minimum age and service requirements. The Company contributions consist of matching amounts and are allocated based on employee contributions. Contributions to the 401(k) plan were $5,348, $4,949, and $3,681 for the years ended April 30, 2014, 2013, and 2012, respectively. On April 30, 2014 and 2013, 1,488,510 and 1,496,465 shares of common stock, respectively, were held by the trustee of the 401(k) plan in trust for distribution to eligible participants upon death, disability, retirement, or termination of employment. Shares held by the 401(k) plan are treated as outstanding in the computation of net income per common share. Supplemental executive retirement plan The Company has a nonqualified supplemental executive retirement plan (SERP) for two of its executive officers, one of whom retired April 30, 2003 and the other on April 30, 2008. The SERP provides for the Company to pay annual retirement benefits, depending on retirement dates, up to 50% of base compensation until death of the officer. If death occurs within twenty years of retirement, the benefits become payable to the officer’s spouse (at a reduced level) until the spouse’s death or twenty years from the date of the officer’s retirement, whichever comes first. The Company has accrued the deferred compensation over the term of employment. The amounts accrued at April 30, 2014 and 2013, respectively, were $5,925 and $6,457. The discount rates used were 4.4% and 4.0%, respectively, at April 30, 2014 and 2013. The amount expensed in fiscal 2014 was $93 and the Company expects to pay $625 per year for each of the next five years. Expense incurred in fiscal 2013 and fiscal 2012 was $471 and $662, respectively. Other postemployment benefits The Company also has deferred compensation agreements with three other individuals, one current and two former employees. The amounts accrued at April 30, 2014 and 2013 were $3,950 and $4,016, respectively. The Company expects to pay $167, $497, $497, $497 and $441 the next five years under the agreements. The expense incurred in fiscal 2014, 2013 and 2012 was $156, $438, and $563 respectively.

Note 8 - Benefit Plans

12 Months Ended

Apr. 30, 2014

Disclosure Text Block Supplement [Abstract]

Compensation and Employee Benefit Plans [Text Block]

8. Benefit plans

401(k) plan The Company provides employees with a defined contribution 401(k) plan. The 401(k) plan covers all employees who meet minimum age and service requirements. The Company contributions consist of matching amounts and are allocated based on employee contributions. Contributions to the 401(k) plan were $5,348, $4,949, and $3,681 for the years ended April 30, 2014, 2013, and 2012, respectively.

On April 30, 2014 and 2013, 1,488,510 and 1,496,465 shares of common stock, respectively, were held by the trustee of the 401(k) plan in trust for distribution to eligible participants upon death, disability, retirement, or termination of employment. Shares held by the 401(k) plan are treated as outstanding in the computation of net income per common share.

Supplemental executive retirement plan The Company has a nonqualified supplemental executive retirement plan (SERP) for two of its executive officers, one of whom retired April 30, 2003 and the other on April 30, 2008. The SERP provides for the Company to pay annual retirement benefits, depending on retirement dates, up to 50% of base compensation until death of the officer. If death occurs within twenty years of retirement, the benefits become payable to the officer’s spouse (at a reduced level) until the spouse’s death or twenty years from the date of the officer’s retirement, whichever comes first. The Company has accrued the deferred compensation over the term of employment. The amounts accrued at April 30, 2014 and 2013, respectively, were $5,925 and $6,457. The discount rates used were 4.4% and 4.0%, respectively, at April 30, 2014 and 2013. The amount expensed in fiscal 2014 was $93 and the Company expects to pay $625 per year for each of the next five years. Expense incurred in fiscal 2013 and fiscal 2012 was $471 and $662, respectively.

Other postemployment benefits The Company also has deferred compensation agreements with three other individuals, one current and two former employees. The amounts accrued at April 30, 2014 and 2013 were $3,950 and $4,016, respectively. The Company expects to pay $167, $497, $497, $497 and $441 the next five years under the agreements. The expense incurred in fiscal 2014, 2013 and 2012 was $156, $438, and $563 respectively.