Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2026	Mar. 31, 2025
Cash Flows from Operating Activities
Net income	$ 2,216	$ 2,288
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization and accretion of premiums and discounts on investments, net	(59)	(97)
Provision for credit losses	71	353
Loans originated for sale		(385)
Proceeds from sale of loans		423
Net gain on sale of loans		(38)
Amortization of intangible assets	7	20
Depreciation and amortization	337	318
Net gain from disposal of premises and equipment	(7)
Deferred income tax expense	498	437
Increase in cash surrender value of insurance	(198)	(188)
Net decrease (increase) in accrued interest receivable	174	(197)
Expense of earned ESOP shares	77	55
Share-based compensation expense	10	9
Net decrease in other assets	3,725	1,057
Net (decrease) increase in accrued expenses and other liabilities	(3,332)	258
Net cash provided by operating activities	3,519	4,313
Cash Flows from Investing Activities
Proceeds from maturities and principal repayments of securities	6,588	18,069
Purchases of securities	(992)	(631)
Net purchases of FHLB Stock	900	715
Net decrease (increase) in loans	16,562	(5,076)
Purchases of bank premises and equipment	(637)	(116)
Proceeds from disposal of premises and equipment	448
Net cash provided by investing activities	22,869	12,961
Cash Flows from Financing Activities
Net increase in demand deposits, NOW, money market and savings accounts	148	21,745
Net increase (decrease) in time deposits	6,004	(8,287)
Net decrease in mortgagors' escrow accounts	(1,509)	(1,799)
Net decrease in short-term debt		(15,900)
Repayment of borrowings	(20,000)
Stock repurchases	(220)
Proceeds from exercise of stock options	107
Net cash used in financing activities	(15,470)	(4,241)
Net increase in cash and cash equivalents	10,918	13,033
Cash and Cash Equivalents
Beginning balance	101,986	37,484
Ending balance	112,904	50,517
Supplemental Disclosures of Cash Flow Information
Interest	5,678	5,743
Income taxes	$ 117	$ 105

Net cash inflow (outflow) of demand deposits, money market and savings accounts

No definition available.

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Namespace Prefix:	rbkb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The sum of the periodic adjustments of the differences between securities' face values and purchase prices that are charged against earnings. This is called accretion if the security was purchased at a discount and amortization if it was purchased at premium. As a noncash item, this element is an adjustment to net income when calculating cash provided by or used in operations using the indirect method.