Condensed Financial Statements of Unity Bancorp, Inc. (Parent Company Only) - Condensed Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
ASSETS
Cash and cash equivalents	$ 145,515	$ 150,254	$ 105,895	$ 88,157
Securities available for sale	46,713	52,287
Premises and equipment, net	23,371	23,470
Prepaid expenses and other assets	8,635	6,358
Total assets	1,579,157	1,455,496
LIABILITIES AND SHAREHOLDERS' EQUITY
Other liabilities	12,266	8,508
Subordinated debentures	10,310	10,310
Shareholders' equity	138,488	118,105	$ 106,291	$ 78,470
Total liabilities and shareholders' equity	1,579,157	1,455,496
Parent Company Only
ASSETS
Cash and cash equivalents	1,209	1,632
Securities available for sale	1,239	278
Investment in subsidiaries	143,487	124,634
Premises and equipment, net	3,893	3,999
Prepaid expenses and other assets	1,372	369
Total assets	151,200	130,912
LIABILITIES AND SHAREHOLDERS' EQUITY
Loan due to subsidiary bank	2,396	2,483
Other liabilities	6	14
Subordinated debentures	10,310	10,310
Shareholders' equity	138,488	118,105
Total liabilities and shareholders' equity	$ 151,200	$ 130,912