v3.7.0.1

Investment in Rental Property and Lease Arrangements - Additional Information (Detail) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017 USD ($) Property	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) Property	Jun. 30, 2016 USD ($)
Lessor Lease Description [Line Items]
Number of real estate properties under operating leases	444		444
Number of real estate properties under direct financing leases	15		15
Number of real estate properties under direct financing leases that include land option	5		5
Lessor, operating lease, existence of option to extend			true
Lessor, direct financing lease, existence of option to extend			true
Depreciation expense on investment in rental property | $	$ 11,924	$ 9,230	$ 23,855	$ 17,528
Minimum
Lessor Lease Description [Line Items]
Lessor operating lease, initial terms			10 years
Lessor direct financing leases, initial terms			10 years
Maximum
Lessor Lease Description [Line Items]
Lessor operating lease, initial terms			20 years
Lessor direct financing leases, initial terms			20 years

X

- Definition

Number of properties classified as direct financing leases.

+ References

No definition available.

+ Details

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X

- Definition

Number of real estate properties under direct financing leases that include land option.

+ References

No definition available.

+ Details

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Namespace Prefix:	ck0001424182_
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Period Type:	instant

X

- Definition

Indicates (true/false) whether lessor has option to extend direct financing lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=77888428&loc=SL77919359-209981

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:booleanItemType
Balance Type:	na
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X

- Definition

Term of lessor's direct financing lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=77888428&loc=SL77919359-209981

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

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

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
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X

- Definition

Term of the lessor's leasing arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
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X

- Definition

Indicates (true/false) whether lessor has option to extend operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=77888428&loc=SL77919359-209981

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:booleanItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The total depreciation charge recorded for property subject to or held for lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

+ Details

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

X

- Definition

The number of units (items of property) under operating lease arrangements.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
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X

- Details

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- Details

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