Regulatory Capital (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Capital conservation buffer	2.50%
Capital conservation buffer period	3 years
Well-capitalized status,Tier 1 capital ratio	8.00%
Significant subsidiary, assets or net income as percentage of consolidated total, threshold	10.00%
Tier I capital
Tier III capital, Actual	$ 2,685,880	$ 2,660,016
Tier III capital, For Capital Adequacy Purposes	1,599,725	1,538,637
Common equity tier I capital (transitional)
Common equity tier 1 capital (transitional), Actual	2,654,287	2,660,016
Common equity tier 1 capital (transitional), For Capital Adequacy Purposes	1,199,794	1,153,977
Total risk-based capital
Total risk-based capital, Actual	3,201,268	3,255,758
Total risk-based capital, For Capital Adequacy Purposes	$ 2,132,966	$ 2,051,515
Tier I capital ratio
Tier III capital ratio, Actual	10.07%	10.37%
Tier III capital ratio, For Capital Adequacy Purposes	6.00%	6.00%
Common equity tier I capital ratio (transitional)
Common equity tier I capital ratio (transitional), Actual	9.96%	10.37%
Common equity tier I capital ratio (transitional), For Capital Adequacy Purposes	4.50%	4.50%
Common equity tier I capital ratio (transitional), To Be Well Capitalized Under Prompt Corrective Action Provisions	6.50%
Total risk-based capital ratio
Total risk-based capital ratio, Actual	12.01%	12.70%
Total risk-based capital ratio, For Capital Adequacy Purposes	8.00%	8.00%
Total risk-based capital ratio, To Be Well Capitalized Under Prompt Corrective Action Provisions	10.00%
Leverage ratio
Leverage ratio, Actual	8.99%	9.43%
Leverage ratio, For Capital Adequacy Purposes	4.00%	4.00%
Leverage ratio, To Be Well Capitalized Under Prompt Corrective Action Provisions	5.00%
Minimum [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Capital conservation buffer	0.625%
Synovus Bank [Member]
Tier I capital
Tier III capital, Actual	$ 3,187,583	$ 3,136,132
Tier III capital, For Capital Adequacy Purposes	1,597,302	1,535,541
Tier III capital, To Be Well Capitalized Under Prompt Corrective Action Provisions	2,129,736	2,047,388
Common equity tier I capital (transitional)
Common equity tier 1 capital (transitional), Actual	3,187,583	3,136,132
Common equity tier 1 capital (transitional), For Capital Adequacy Purposes	1,197,976	1,151,656
Common equity tier 1 capital (transitional), To Be Well Capitalized Under Prompt Corrective Action Provisions	1,730,410	1,663,503
Total risk-based capital
Total risk-based capital, Actual	3,441,563	3,390,764
Total risk-based capital, For Capital Adequacy Purposes	2,129,736	2,047,388
Total risk-based capital, To Be Well Capitalized Under Prompt Corrective Action Provisions	$ 2,662,169	$ 2,559,235
Tier I capital ratio
Tier III capital ratio, Actual	11.97%	12.25%
Tier III capital ratio, For Capital Adequacy Purposes	6.00%	6.00%
Tier III capital ratio, To Be Well Capitalized Under Prompt Corrective Action Provisions	8.00%	8.00%
Common equity tier I capital ratio (transitional)
Common equity tier I capital ratio (transitional), Actual	11.97%	12.25%
Common equity tier I capital ratio (transitional), For Capital Adequacy Purposes	4.50%	4.50%
Common equity tier I capital ratio (transitional), To Be Well Capitalized Under Prompt Corrective Action Provisions	6.50%	6.50%
Total risk-based capital ratio
Total risk-based capital ratio, Actual	12.93%	13.25%
Total risk-based capital ratio, For Capital Adequacy Purposes	8.00%	8.00%
Total risk-based capital ratio, To Be Well Capitalized Under Prompt Corrective Action Provisions	10.00%	10.00%
Leverage ratio
Leverage ratio, Actual	10.68%	11.15%
Leverage ratio, For Capital Adequacy Purposes	4.00%	4.00%
Leverage ratio, To Be Well Capitalized Under Prompt Corrective Action Provisions	5.00%	5.00%