Condensed Financial Statements of United Community Banks, Inc. (Holding Company Only) - Statements of Income (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Operations
Dividends from bank	$ 0	$ 162,000,000
Total income	560,957,000	522,211,000	$ 440,445,000
Interest expense	83,312,000	61,330,000	33,735,000
Other expense	15,092,000	17,194,000	12,962,000
Total expenses	322,245,000	306,285,000	267,611,000
Income tax benefit (expense)	(52,991,000)	(49,815,000)	(105,013,000)
Net income	185,721,000	166,111,000	67,821,000
Holding Company
Statement of Operations
Dividends from bank	0	161,500,000	103,200,000
Dividends from other subsidiaries	4,651,000	850,000	0
Shared service fees from subsidiaries	14,721,000	10,257,000	10,481,000
Other	1,468,000	133,000	1,078,000
Total income	20,840,000	172,740,000	114,759,000
Interest expense	11,573,000	11,868,000	10,258,000
Other expense	18,965,000	14,456,000	14,960,000
Total expenses	30,538,000	26,324,000	25,218,000
Income tax benefit (expense)	8,711,000	1,640,000	1,447,000
Income before equity in undistributed (loss) earnings of subsidiaries	(987,000)	148,056,000	90,988,000
Equity in undistributed (loss) earnings of subsidiaries	186,708,000	18,055,000	(23,167,000)
Net income	$ 185,721,000	$ 166,111,000	$ 67,821,000