Derivatives and Hedging Activities - Schedule of Derivative Instruments (Details) - Cash Flow Hedging - Interest Rate Cap	6 Months Ended	12 Months Ended
Jun. 30, 2019 USD ($) instrument	Dec. 31, 2018 USD ($) instrument
Derivatives, Fair Value [Line Items]
Number of Instruments \| instrument	2	2
Notional Amount \| $	$ 54,145,000	$ 54,145,000
Maturity Dates, Earliest	Aug. 01, 2020	Aug. 01, 2020
Maturity Dates, Latest	Apr. 01, 2021	Apr. 01, 2021

Derivative maturity date earliest.

No definition available.

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Namespace Prefix:	ck0001652926_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Derivative maturity date latest.

+ References

No definition available.

+ Details

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Namespace Prefix:	ck0001652926_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

+ Details

Name:	invest_DerivativeNotionalAmount
Namespace Prefix:	invest_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- 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

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of interest rate derivative instruments held by the entity at the reporting date.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5579245-113959

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5580258-113959

+ Details

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Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Details

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Namespace Prefix:
Data Type:	na
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Period Type:

- Details

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