Condensed Financial Statements of Unity Bancorp, Inc. (Parent Company Only) - Condensed Statements of Income (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
Condensed Financial Statements, Captions [Line Items]
Dividend from Bank	$ 40,264	$ 39,550	$ 37,987	$ 37,937	$ 37,758	$ 36,990	$ 35,392	$ 33,354	$ 155,738	$ 143,494
Gain on sales of securities									586	7
Other income									1,635	1,513
Total noninterest income	1,916	2,803	2,032	1,718	2,568	2,043	2,115	1,416	8,469	8,142
Interest expenses	13,774	14,694	14,563	14,096	13,727	13,457	11,870	9,443	57,127	48,497
Other expenses									2,707	2,585
Net Income (Loss)	$ 11,505	$ 10,905	$ 9,454	$ 9,586	$ 9,770	$ 9,950	$ 9,700	$ 10,287	41,450	39,707
Parent Company [Member] | Reportable Legal Entities [Member]
Condensed Financial Statements, Captions [Line Items]
Dividend from Bank									6,196	15,188
Dividend from Nonbank subsidiary										1,235
Gain on sales of securities									54	345
Market value appreciation on equity securities									575
Other income									793	760
Total noninterest income									7,618	17,528
Interest expenses									718	695
Market value depreciation on equity securities										444
Other expenses									170	265
Total expenses									888	1,404
Income before provision for income taxes and equity in undistributed net income of subsidiary									6,730	16,124
Income tax expense (benefit)									121	(114)
Income before equity in undistributed net income of subsidiary									6,609	16,238
Equity in undistributed net income of subsidiaries									34,841	23,469
Net Income (Loss)									$ 41,450	$ 39,707