Condensed Financial Information Of Synovus Financial Corp. (Parent Company Only) - Condensed Statements of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating Activities
Net income	$ 757,902	$ 760,467	$ 373,695
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Other	677	0	55,343
Net cash provided by operating activities	1,191,489	794,016	17,032
Investing Activities
Net cash used in investing activities	(4,855,482)	(4,384,166)	(2,352,973)
Financing Activities
Repurchase of common stock	(12,987)	(199,932)	(16,246)
Repayments and redemption of long-term debt	(700,000)	0	(2,408,939)
Proceeds from long-term debt, net	3,622,892	0	1,445,492
Other	0	(1,104)	(1,552)
Net cash provided by financing activities	2,631,920	2,347,086	5,401,940
Increase (decrease) in cash and cash equivalents including restricted cash	(1,032,073)	(1,243,064)	3,065,999
Cash, cash equivalents, and restricted cash at beginning of year	3,009,853	4,252,917	1,186,918
Cash, cash equivalents, and restricted cash at end of year	1,977,780	3,009,853	4,252,917
Income taxes paid	175,680	204,214	110,828
Interest paid	242,040	132,923	319,282
Parent Company
Operating Activities
Net income	757,902	760,467	373,695
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Equity in undistributed (income) loss of subsidiaries	(448,555)	(368,702)	140,819
Deferred income tax expense (benefit)	143	(7,296)	3,962
Net increase (decrease) in other liabilities	3,233	(2,082)	11,243
Net (increase) decrease in other assets	8,022	5,280	17,441
Other	825	928	(5,132)
Net cash provided by operating activities	321,570	388,595	542,028
Investing Activities
Proceeds from sales of equity securities	0	0	23,141
Increase in other investments	(1,027)	(10,000)	0
Net cash used in investing activities	(1,027)	(10,000)	23,141
Financing Activities
Dividends paid to common and preferred shareholders	(229,311)	(227,840)	(223,130)
Repurchase of common stock	(12,987)	(199,932)	(16,246)
Repayments and redemption of long-term debt	(300,000)	0	(250,000)
Proceeds from long-term debt, net	347,892	0	0
Other	0	(1,104)	(1,552)
Net cash provided by financing activities	(194,406)	(428,876)	(490,928)
Increase (decrease) in cash and cash equivalents including restricted cash	126,137	(50,281)	74,241
Cash, cash equivalents, and restricted cash at beginning of year	398,348	448,629	374,388
Cash, cash equivalents, and restricted cash at end of year	524,485	398,348	448,629
Income taxes paid	173,900	203,200	119,100
Interest paid	$ 29,900	$ 27,300	$ 42,000