Condensed Financial Statements of United Community Banks, Inc. (Holding Company Only) - Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
ASSETS
Cash	$ 515,206	$ 327,265
Other assets	171,135	154,750
Total assets	12,916,016	12,573,192
LIABILITIES AND SHAREHOLDERS’ EQUITY
Long-term debt	212,664	267,189
Total liabilities	11,280,324	11,115,638
Shareholders' equity	1,635,692	1,457,554	$ 1,303,334	$ 1,075,735
Total liabilities and shareholders’ equity	12,916,016	12,573,192
Holding Company
ASSETS
Cash	32,495	145,669
Investment in bank	1,814,414	1,522,402
Investment in other subsidiaries	752	4,549
Other assets	29,308	21,881
Total assets	1,876,969	1,694,501
LIABILITIES AND SHAREHOLDERS’ EQUITY
Long-term debt	212,664	212,193
Other liabilities	28,613	24,754
Total liabilities	241,277	236,947
Shareholders' equity	1,635,692	1,457,554
Total liabilities and shareholders’ equity	$ 1,876,969	$ 1,694,501