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Income Taxes - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified | 12 Months Ended |
--- | --- | ---
Apr. 30, 2014 | Apr. 30, 2013 | Jan. 18, 2011
Income Taxes [Line Items] |  |  |
Income tax settlement amount |  | $ 800 |
Tax paid for income tax settlement |  | 430 |
Interest paid for income tax settlement |  | 370 |
Aggregate finance asserting liability total |  |  | 3,852
Taxation payable |  |  | 2,220
Penalties and interest payable |  |  | 1,632
Potential cumulative liability |  | 8.00% |
Net operating loss carryforwards | 73,772 |  |
Net operating loss carryforwards expiry period | 2024 through 2034 |  |
State net operating loss carryforwards expiry period | 93,680 |  |
Net operating loss carryforwards benefit recorded additional paid-in capital | 383 |  |
Alternative minimum tax credit carryforwards | 3,330 | 3,330 |
General business tax credit carryforwards | 2,666 | 2,095 |
General business tax credit carryforwards expiration date | 2023 through 2034 |  |
Capital loss carryforward | 2,510 |  |
Capital loss carryforward expiration period | 2019 |  |
Valuation allowance | 14,188 |  |
Settlements |  | (430) |
Unrecognized tax benefit net of federal benefit on state issue | 0 | 0 |
Unrecognized tax benefits | 0 |  |
Uncertain tax positions, accrued interest | 116 | 76 |
Uncertain tax positions, penalties | 8 | 9 |
Accrued income tax expense | 40 | 41 |
Business Acquisition [Member] |  |  |
Income Taxes [Line Items] |  |  |
Increase (decrease) in valuation allowance | 5,084 | (5,084) |
State [Member] |  |  |
Income Taxes [Line Items] |  |  |
Net operating loss carryforwards expiry period | 2015 through 2034 |  |
2019 Year [Member] |  |  |
Income Taxes [Line Items] |  |  |
Capital loss carryforward | $ 6,235 |  |

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