Share-based compensation (Details) (USD $) | 12 Months Ended |
In Thousands, except Share data, unless otherwise specified | Sep. 30, 2013 | Sep. 30, 2012 | Sep. 30, 2011 |
| Plans |
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] | ' | ' | ' |
Share Based Compensation Number Of Plans | 3 | ' | ' |
Allocated Share-based Compensation Expense | $1 | $1 | $1 |
Income Tax Expense (Benefit) | 1,402 | 145 | 495 |
Share-based compensation expense remaining capitalized in inventory | 21 | 11 | 12 |
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized | 2,000 | ' | ' |
Share Based Compensation Arrangement By Share Based Payment Award, Equity Instruments Other Than Options, Expected to Vest, Outstanding, Number | 5,304 | ' | ' |
Cost of goods sold | ' | ' | ' |
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] | ' | ' | ' |
Allocated Share-based Compensation Expense | 0 | 0 | 0 |
Operating expenses | ' | ' | ' |
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] | ' | ' | ' |
Allocated Share-based Compensation Expense | 1 | 1 | 1 |
Stock Compensation Plan | ' | ' | ' |
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] | ' | ' | ' |
Income Tax Expense (Benefit) | 0 | 0 | 1 |
Service-based Stock Awards | ' | ' | ' |
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] | ' | ' | ' |
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized | 1,900 | ' | ' |
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition | '2 years 1 month 2 days | ' | ' |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period | 178,163 | 95,805 | 53,470 |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Total Fair Value | 1,500 | 900 | 1,600 |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value | $11.65 | $13.06 | $17.89 |
Performance-Based Stock Awards | ' | ' | ' |
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] | ' | ' | ' |
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized | 78 | ' | ' |
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition | '1 year 6 months 18 days | ' | ' |
Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period | '3 years | '3 years | ' |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period | 103,026 | 92,910 | 60,212 |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Total Fair Value | ' | ' | 245 |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value | $14.67 | $11.20 | $17.37 |
Employee Stock Purchase Plan | ' | ' | ' |
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] | ' | ' | ' |
Employee Service Share-based Compensation, Cash Received from Exercise of Stock Options | 95 | 94 | 147 |
Incentive Stock Options | ' | ' | ' |
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] | ' | ' | ' |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term | '0 years 10 months 6 days | ' | ' |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value | 66 | 108 | 44 |
Non Employee Service Based Stock Awards | ' | ' | ' |
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] | ' | ' | ' |
Employee Service Share-based Compensation, Tax Benefit Realized from Exercise of Stock Options | $453 | $392 | $642 |
Employees Stock Incentive Plan | ' | ' | ' |
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] | ' | ' | ' |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized | 672,474 | ' | ' |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant | 220,193 | ' | ' |
Employee Stock Purchase Plan | ' | ' | ' |
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] | ' | ' | ' |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized | 500,000 | ' | ' |
Share Based Compensation Arrangement By Share Based Payment Award Maximum Employee Stock Ownership | 5.00% | ' | ' |
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Employee Subscription Rate | 5.00% | ' | ' |
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent | 85.00% | ' | ' |
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number | 357,769 | ' | ' |
Stock Issued During Period, Shares, Employee Stock Purchase Plans | 6,257 | 8,417 | 8,269 |
SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercentDiscount | 15.00% | ' | ' |
Minimum | Service-based Stock Awards | ' | ' | ' |
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] | ' | ' | ' |
Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period | '2 years | ' | ' |
Maximum | Service-based Stock Awards | ' | ' | ' |
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] | ' | ' | ' |
Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period | '3 years | ' | ' |
Maximum | Employees Stock Incentive Plan | Stock options | ' | ' | ' |
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] | ' | ' | ' |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term | '10 years | ' | ' |
Executive | Maximum | Service-based Stock Awards | ' | ' | ' |
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] | ' | ' | ' |
Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period | '3 years | ' | ' |
Board of Directors Chairman | Maximum | Service-based Stock Awards | ' | ' | ' |
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] | ' | ' | ' |
Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period | '1 year | ' | ' |
Shares Vest In One Year | Service-based Stock Awards | ' | ' | ' |
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] | ' | ' | ' |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period | 49,294 | ' | ' |
Shares Vest In Two Years | Service-based Stock Awards | ' | ' | ' |
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] | ' | ' | ' |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period | 32,873 | ' | ' |
Shares Vest In Three Years | Service-based Stock Awards | ' | ' | ' |
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] | ' | ' | ' |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period | 95,996 | ' | ' |