Derivative Financial Instruments - Additional Information (Details) $ in Millions	Mar. 31, 2021 USD ($)
Interest Rate Cap [Member]
Amount Of Debt Covered By Derivatives	$ 280.5

The total amount of variable debt covered by the derivatives.

No definition available.

Name:	brg_AmountOfDebtCoveredByDerivatives
Namespace Prefix:	brg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant