Share-Based Compensation - Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands | 3 Months Ended | 12 Months Ended | | |
Sep. 30, 2017 | Sep. 30, 2016 | Jun. 30, 2016 | Sep. 30, 2017 | Jun. 30, 2017 |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | |
Proceeds from stock option exercises | $ 0 | $ 84 | | | |
Non-qualified Stock Options with Time-based Vesting (NQO) [Member] | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value | | 0 | | | |
Proceeds from stock option exercises | | 100 | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract] | | | | | |
Weighted Average Remaining Life, Beginning balance | | | 2 years 7 months 6 days | | |
Weighted Average Remaining Life, Ending balance | | | 2 years 7 months 6 days | | |
Aggregate Intrinsic Value, Beginning balance | | | | | $ 2,299 |
Non-qualified Stock Options with Time-based Vesting (NQO) [Member] | Vested | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] | | | | | |
Number of options - Beginning balance (in shares) | 133,464 | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] | | | | | |
Weighted Average Exercise Price, Beginning balance (in US$ per share) | $ 13.05 | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract] | | | | | |
Weighted Average Grant Date Fair Value, Beginning balance (in US$ per share) | 5.99 | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest [Abstract] | | | | | |
Options, Vested and exercisable, Outstanding (in shares) | | | | 125,376 | |
Options, Vested and exercisable, Weighted Average Exercise Price (in US$ per share) | | | | $ 12.13 | |
Options, Vested and exercisable, Weighted Average Grant Date Fair Value (in US$ per share) | $ 5.64 | | | | |
Options, Vested and exercisable, Weighted Average Remaining Contractual Term | 1 year 10 months 24 days | | | | |
Options, Vested and exercisable, Aggregate Intrinsic Value | | | | $ 2,598 | |
Options, Vested and expected to vest, Outstanding (in shares) | | | | 129,108 | |
Options, Vested and expected to vest, Weighted Average Exercise Price (in US$ per share) | | | | $ 12.66 | |
Options, Vested and expected to vest, Weighted Average Grant Date Fair Value (in US$ per share) | $ 5.83 | | | | |
Options, Vested and expected to vest, Exercisable, Weighted Average Remaining Life | 2 years | | | | |
Options, Vested and expected to vest, Aggregate Intrinsic Value | | | | $ 2,607 | |
Non-qualified Stock Options with Time-based Vesting (NQO) [Member] | Farmer Bros. Co. Amended and Restated 2007 Long-term Incentive Plan | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Number of Shares | 0 | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] | | | | | |
Number of options granted (shares) | 0 | | | | |
Number of options exercised (shares) | 0 | | | | |
Number of options cancelled/forfeited (shares) | (4,194) | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] | | | | | |
Weighted average purchase price (in US$ per share) | $ 0 | | | | |
Weighted Average Exercise Price, Exercised (in US$ per share) | 0 | | | | |
Weighted Average Exercise Price, Cancelled/Forfeited (in US$ per share) | 24.41 | | | | |
Weighted Average Exercise Price, Ending balance (in US$ per share) | 12.68 | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract] | | | | | |
Weighted average fair value (in US$ per share) | 0 | | | | |
Weighted Average Grant Date Fair Value, Exercised (in US$ per share) | 0 | | | | |
Weighted Average Grant Date Fair Value, Cancelled/Forfeited (in US$ per share) | 10.60 | | | | |
Weighted Average Grant Date Fair Value, Ending balance (in US$ per share) | $ 5.84 | | | | |
Weighted Average Remaining Life, Beginning balance | 2 years | | | | |
Weighted Average Remaining Life, Ending balance | 2 years | | | | |
Aggregate Intrinsic Value, Beginning balance | $ 2,608 | | | $ 2,608 | |
Aggregate intrinsic value, exercised | 0 | | | | |
Aggregate Intrinsic Value, Cancelled/Forfeited | 0 | | | | |
Aggregate Intrinsic Value, Ending balance | $ 2,608 | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest [Abstract] | | | | | |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Outstanding Options | | | | 129,270 | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Grant Date Intrinsic Value | $ 0 | | | | |
PNQs | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | |
Proceeds from stock option exercises | | $ 100 | | | |
PNQs | Farmer Bros. Co. Amended and Restated 2007 Long-term Incentive Plan | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Number of Shares | 0 | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] | | | | | |
Number of options - Beginning balance (in shares) | 358,786 | | | | |
Number of options granted (shares) | 0 | | | | |
Number of options exercised (shares) | 0 | | | | |
Number of options cancelled/forfeited (shares) | (24,622) | | | | |
Number of options - Ending balance (in shares) | 334,164 | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] | | | | | |
Weighted average purchase price (in US$ per share) | $ 0 | | | | |
Weighted Average Exercise Price, Exercised (in US$ per share) | 0 | | | | |
Weighted Average Exercise Price, Cancelled/Forfeited (in US$ per share) | 31.54 | | | | |
Weighted Average Exercise Price, Ending balance (in US$ per share) | 27.75 | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract] | | | | | |
Weighted average fair value (in US$ per share) | 0 | | | | |
Weighted Average Grant Date Fair Value, Exercised (in US$ per share) | 0 | | | | |
Weighted Average Grant Date Fair Value, Cancelled/Forfeited (in US$ per share) | 11.44 | | | | |
Weighted Average Grant Date Fair Value, Ending balance (in US$ per share) | $ 10.96 | | | | |
Weighted Average Remaining Life, Beginning balance | 5 years 2 months 9 days | | | | |
Weighted Average Remaining Life, Ending balance | 5 years 2 months 9 days | | | | |
Aggregate Intrinsic Value, Beginning balance | $ 1,181 | | | $ 1,181 | |
Aggregate intrinsic value, exercised | 0 | | | | |
Aggregate Intrinsic Value, Cancelled/Forfeited | 0 | | | | |
Aggregate Intrinsic Value, Ending balance | $ 1,181 | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest [Abstract] | | | | | |
Options, Vested and exercisable, Outstanding (in shares) | | | | 150,761 | |
Options, Vested and exercisable, Weighted Average Exercise Price (in US$ per share) | | | | $ 23.97 | |
Options, Vested and exercisable, Weighted Average Grant Date Fair Value (in US$ per share) | $ 10.58 | | | | |
Options, Vested and exercisable, Weighted Average Remaining Contractual Term | 3 years 11 months 5 days | | | | |
Options, Vested and exercisable, Aggregate Intrinsic Value | | | | $ 1,339 | |
Options, Vested and expected to vest, Outstanding (in shares) | | | | 326,704 | |
Options, Vested and expected to vest, Weighted Average Exercise Price (in US$ per share) | | | | $ 27.38 | |
Options, Vested and expected to vest, Weighted Average Grant Date Fair Value (in US$ per share) | $ 10.92 | | | | |
Options, Vested and expected to vest, Exercisable, Weighted Average Remaining Life | 4 years 9 months 15 days | | | | |
Options, Vested and expected to vest, Aggregate Intrinsic Value | | | | $ 1,788 | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Grant Date Intrinsic Value | $ 0 | | | | |