Condensed Financial Information Of Synovus Financial Corp. (Parent Company Only) (Condensed Statements of Comprehensive Income) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Condensed Financial Statements, Captions [Line Items]
Net income, Before-tax Amount									$ 358,573	$ 302,559	$ 252,628
Allocated income tax benefit	$ (32,342)	$ (36,058)	$ (32,242)	$ (31,849)	$ (25,756)	$ (25,868)	$ (27,078)	$ (28,608)	(132,491)	(107,310)	(93,245)
Net income	$ 58,398	$ 57,928	$ 55,792	$ 53,963	$ 53,173	$ 46,788	$ 46,872	$ 48,416	226,082	195,249	159,383
Reclassification adjustment for losses (gains) realized in net income, Before-tax Amount									521	448	447
Reclassification adjustment for losses (gains) realized in net income, Tax (Expense) Benefit									(201)	(173)	(173)
Reclassification adjustment for losses (gains) realized in net income, Net of Tax Amount									320	275	274
Net unrealized gains (losses) arising during the period, Before-tax Amount									(25,707)	47,223	(71,929)
Net unrealized gains (losses) arising during the period, Tax (Expense) Benefit									9,901	(18,182)	27,693
Net unrealized gains (losses) arising during the period, Net of Tax Amount									(15,806)	29,041	(44,236)
Other comprehensive income (loss), Before-tax Amount									(27,991)	46,591	(73,767)
Other comprehensive income (loss), Tax (Expense) Benefit									10,777	(17,938)	28,408
Other comprehensive income (loss), Net of Tax Amount									(17,214)	28,653	(45,359)
Comprehensive income, Net of Tax Amount									208,868	223,902	114,024
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Net income, Before-tax Amount									358,573	302,559	252,628
Allocated income tax benefit									(132,491)	(107,310)	(93,245)
Net income									226,082	195,249	159,383
Reclassification adjustment for losses (gains) realized in net income, Before-tax Amount									521	448	447
Reclassification adjustment for losses (gains) realized in net income, Tax (Expense) Benefit									(201)	(173)	(173)
Reclassification adjustment for losses (gains) realized in net income, Net of Tax Amount									320	275	274
Net unrealized gains (losses) arising during the period, Before-tax Amount									2,908	21	3,246
Net unrealized gains (losses) arising during the period, Tax (Expense) Benefit									(1,120)	(8)	(1,250)
Net unrealized gains (losses) arising during the period, Net of Tax Amount									1,788	13	1,996
Other comprehensive gain (loss) of bank subsidiary, Before-tax Amount									(31,420)	46,122	(77,460)
Other comprehensive gain (loss) of bank subsidiary, Tax (expense) Benefit									12,098	(17,757)	29,831
Other comprehensive gain (loss) of bank subsidiary, Net of Tax Amount									(19,322)	28,365	(47,629)
Other comprehensive income (loss), Before-tax Amount									(27,991)	46,591	(73,767)
Other comprehensive income (loss), Tax (Expense) Benefit									10,777	(17,938)	28,408
Other comprehensive income (loss), Net of Tax Amount									(17,214)	28,653	(45,359)
Comprehensive income, Net of Tax Amount									$ 208,868	$ 223,902	$ 114,024