v3.10.0.1

Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Millions | Sep. 30, 2018 | Dec. 31, 2017
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Commitments And Contingencies Disclosure [Abstract] |  |
Outstanding borrowings | $ 295.5 | $ 291.0

X
- Definition Line of credit facility gross amount borrowed. + References No definition available. + Details
Name: | arex_LineOfCreditFacilityGrossAmountBorrowed
Namespace Prefix: | arex_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_CommitmentsAndContingenciesDisclosureAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration