Condensed Financial Statements of Unity Bancorp, Inc. (Parent Company Only) - Condensed Statements of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2024	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2024	Dec. 31, 2023
OPERATING ACTIVITIES:
Net Income (Loss)	$ 11,505	$ 10,905	$ 9,454	$ 9,586	$ 9,770	$ 9,950	$ 9,700	$ 10,287	$ 41,450	$ 39,707
Adjustments to reconcile net income to net cash provided by operating activities:
Gain on sales of securities									(586)	(7)
Net accretion of purchase premiums and discounts on securities									(256)	(264)
Net cash provided by operating activities									47,987	46,909
INVESTING ACTIVITIES:
Purchases of securities									(2,247)	(126)
Maturities and principal payments on debt securities available for sale									7,824	4,286
Purchases of premises and equipment, net									(693)	(955)
Net cash used in investing activities									(92,813)	(57,847)
FINANCING ACTIVITIES:
Proceeds from exercise of stock options, net of withheld taxes									1,480	1,284
Purchase of treasury stock									(6,210)	(15,692)
Cash dividends on common stock									(5,021)	(4,721)
Net cash provided by financing activities									30,488	90,921
Increase (decrease) in cash and cash equivalents									(14,338)	79,983
Cash and cash equivalents, beginning of period				194,776				114,793	194,776	114,793
Cash and cash equivalents, end of period	180,438				194,776				180,438	194,776
Parent Company [Member] | Reportable Legal Entities [Member]
OPERATING ACTIVITIES:
Net Income (Loss)									41,450	39,707
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in undistributed net income of subsidiaries									(34,841)	(23,469)
Gain on sales of securities									(54)	(345)
Net accretion of purchase premiums and discounts on securities									(17)
Net change in other assets and other liabilities									280	349
Net cash provided by operating activities									6,818	16,242
INVESTING ACTIVITIES:
Purchases of securities									(247)	(126)
Proceeds from business divestitures										2,034
Maturities and principal payments on debt securities available for sale									1,495
Purchases of premises and equipment, net									(160)
Proceeds from sales of securities									785	2,166
Net cash used in investing activities									1,873	4,074
FINANCING ACTIVITIES:
Proceeds from exercise of stock options, net of withheld taxes									1,480	1,284
Repayment of advances from subsidiaries										(2,002)
Purchase of treasury stock									(6,210)	(15,692)
Cash dividends on common stock									(5,021)	(4,721)
Net cash provided by financing activities									(9,751)	(21,131)
Increase (decrease) in cash and cash equivalents									(1,060)	(815)
Cash and cash equivalents, beginning of period				$ 1,410				$ 2,225	1,410	2,225
Cash and cash equivalents, end of period	$ 350				$ 1,410				350	1,410
SUPPLEMENTAL DISCLOSURES
Interest paid									$ 722	$ 786