Share-based Compensation and Other Employment Benefit Plans (Grants Under All Synovus Equity Compensation Plan) (Details) - Shareholder approved equity compensation plans for shares of Synovus stock	Dec. 31, 2018 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of securities to be issued upon vesting of restricted share units (in shares)	918,139
Number of securities to be issued upon exercise of outstanding options (in shares)	639,901
Weighted-average exercise price of outstanding options (in dollars per share) | $ / shares	$ 16.93
Number of shares remaining available for issuance excluding shares discussed (in shares)	4,849,161