Condensed Financial Statements of Unity Bancorp, Inc. (Parent Company Only) - Condensed Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
ASSETS
Cash and cash equivalents	$ 244,818	$ 219,311
Equity securities	8,566	1,954
Premises and equipment, net	19,914	20,226
Prepaid expenses and other assets	11,213	8,858
Total assets	2,033,713	1,958,914
LIABILITIES AND SHAREHOLDERS' EQUITY
Other liabilities	18,664	16,486
Subordinated debentures	10,310	10,310
Shareholders' equity	205,729	173,911	$ 160,709	$ 138,488
Total liabilities and shareholders' equity	2,033,713	1,958,914
Parent Company Only | Reportable Legal Entities
ASSETS
Cash and cash equivalents	1,685	640
Equity securities	5,043	1,003
Investment in subsidiaries	207,799	181,113
Premises and equipment, net	3,709	3,823
Prepaid expenses and other assets		52
Total assets	218,236	186,631
LIABILITIES AND SHAREHOLDERS' EQUITY
Loan due to subsidiary bank	2,108	2,209
Other liabilities	89	201
Subordinated debentures	10,310	10,310
Shareholders' equity	205,729	173,911
Total liabilities and shareholders' equity	$ 218,236	$ 186,631