Investment Securities (Details Narrative) - USD ($)	Mar. 31, 2020	Dec. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Investment securities pledged to secure deposits, fair value	$ 38,300,000	$ 37,600,000

Carrying amount of securities pledged to secure deposits and repurchase agreements.

No definition available.

Name:	bksc_CarryingAmountOfSecuritiesPledgedToSecureDepositsAndRepurchaseAgreements
Namespace Prefix:	bksc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant