Stockholders' Equity - Narrative (Details)	Jan. 01, 2018	Dec. 31, 2017	Jan. 01, 2015
Equity [Abstract]
Tier one capital conservation buffer common equity capital to risk weighted assets (greater than)	1.875%	0.625%	2.50%

Tier One Capital Conservation Buffer Common Equity Capital to Risk Weighted Assets

No definition available.

Name:	bhbk_TierOneCapitalConservationBufferCommonEquityCapitaltoRiskWeightedAssets
Namespace Prefix:	bhbk_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant