v3.19.3.a.u2

Commitments and Contingencies - Summary of Tenant Improvement Allowances Included in Accounts Payable and Other Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Accounts Payable And Other Liabilities
Loss Contingencies [Line Items]
Tenant improvement allowances	$ 2,706	$ 2,125

X

- Definition

Tenant improvement allowances.

+ References

No definition available.

+ Details

Name:	ck1424182_TenantImprovementAllowances
Namespace Prefix:	ck1424182_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

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

X

- Details

Name:	us-gaap_BalanceSheetLocationAxis=us-gaap_AccountsPayableAndAccruedLiabilitiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: