Condensed Financial Statements of Parent Company - Condensed Statements of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Cash flows from operating activities
Net income	$ 20,237	$ 20,949
Adjustments to reconcile net income to net cash used in operating activities:
Increase (decrease) in accrued expenses	957	2,203
Net cash provided by operating activities	15,594	21,797
Cash flows from investing activities
Net cash used in investing activities	(163,048)	(97,275)
Cash flows from financing activities
Net proceeds from common stock issued	0	36,540
Repayment of short-term borrowings	0	(5,000)
Net cash provided by financing activities	323,345	169,450
Net increase in cash and cash equivalents	175,891	93,972
Cash and cash equivalents, beginning of period	410,739	316,767
Cash and cash equivalents, end of period	586,630	410,739
Parent Company
Cash flows from operating activities
Net income	20,237	20,949
Adjustments to reconcile net income to net cash used in operating activities:
Undistributed net income of Chain Bridge Bank, N.A.	(22,409)	(22,178)
Decrease (increase) in receivable from subsidiary	(59)	75
Increase in other assets	(79)	0
Increase (decrease) in accrued expenses	(117)	331
Net cash provided by operating activities	(2,427)	(823)
Cash flows from investing activities
Investment in Chain Bridge Bank, N.A.	(12,000)	(5,000)
Net cash used in investing activities	(12,000)	(5,000)
Cash flows from financing activities
Net proceeds from common stock issued	0	36,540
Repayment of short-term borrowings	0	(5,000)
Net cash provided by financing activities	0	31,540
Net increase in cash and cash equivalents	(14,427)	25,717
Cash and cash equivalents, beginning of period	25,760	43
Cash and cash equivalents, end of period	$ 11,333	$ 25,760