v3.7.0.1

Non-Controlling Interests - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Noncontrolling Interest [Abstract]
Properties contributed as part of UPREIT transactions, value			$ 8,278	$ 7,190
Rental income related to UPREIT transactions	$ 2,960	$ 2,927	$ 5,964	$ 5,729

X

- Definition

Noncontrolling interest property contribution.

+ References

No definition available.

+ Details

Name:	ck0001424182_NoncontrollingInterestPropertyContribution
Namespace Prefix:	ck0001424182_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

Amount after tax of income (loss) from continuing operations attributable to the noncontrolling interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 45
-Paragraph 19
-URI http://asc.fasb.org/extlink&oid=96868048&loc=SL4569616-111683

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 45
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=96868048&loc=SL4568447-111683

+ Details

Name:	us-gaap_IncomeLossFromContinuingOperationsAttributableToNoncontrollingEntity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- References

No definition available.

+ Details

Name:	us-gaap_NoncontrollingInterestAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration