XML 94 R78.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Employee Benefit Plans (Schedule of PSUs Earned and Vested Based on Stock Price Appreciation (Stock Price PSUs)) (Details) - Stock Price PSU | 12 Months Ended
--- | ---
Jun. 30, 2018
At least $8.96 but less than $11.63 |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
PSUs, Shares earned | 33.33%
At least $11.63 but less than $13.15 |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
PSUs, Shares earned | 66.67%
At least $13.15 but less than $16.56 |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
PSUs, Shares earned | 100.00%
$16.56 or more |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
PSUs, Shares earned | 133.33%

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of vesting of share-based compensation awards. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
Name: | us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_AwardTypeAxis=extr_StockPriceAppreciationPerformanceSharesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_VestingAxis=extr_AverageAdjustedClosingStockPriceRangeOneMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_VestingAxis=extr_AverageAdjustedClosingStockPriceRangeTwoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_VestingAxis=extr_AverageAdjustedClosingStockPriceRangeThreeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_VestingAxis=extr_AverageAdjustedClosingStockPriceRangeFourMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |