Long-term Debt and Short-term Borrowings (Schedule of Long-term Debt Instruments) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 07, 2015	Dec. 31, 2013
Debt Instrument [Line Items]
Long-term debt	$ 2,186,893,000	$ 2,139,325,000
Interest rate at period end	0.08%	0.08%		0.13%
7.875% Senior Notes due February 15, 2019 [Member] | To be paid at Maturity [Member]
Debt Instrument [Line Items]
Extinguishment of debt, amount	$ 300,000,000
5.75% Subordinated Notes, Due December 15, 2025 [Member]
Debt Instrument [Line Items]
Subordinated notes			$ 250,000,000
Parent Company [Member]
Debt Instrument [Line Items]
Hedge-related basis adjustments	4,018,000	$ 7,607,000
Long-term debt	960,185,000	762,272,000
Parent Company [Member] | 5.125% Subordinated Notes due June 15, 2017 [Member]
Debt Instrument [Line Items]
Subordinated notes	$ 402,812,000	$ 449,006,000
Stated percentage	5.125%	5.125%
Debt, face amount	$ 403,300,000.0	$ 450,000,000
Parent Company [Member] | 7.875% Senior Notes due February 15, 2019 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Long-term debt	296,711,000	295,659,000
Parent Company [Member] | 5.75% Subordinated Notes, Due December 15, 2025 [Member]
Debt Instrument [Line Items]
Subordinated notes	246,644,000	$ 0
Stated percentage		5.75%
Debt, face amount	$ 250,000,000
Parent Company [Member] | 5.75% Subordinated Notes, Due December 15, 2025 [Member] | Three- month LIBOR [Member]
Debt Instrument [Line Items]
Basis spread on variable rate	4.182%
Parent Company [Member] | LIBOR Plus 1.80% debentures, due April 19, 2035 with quarterly interest payments and principal to be paid at maturity (rate of 2.04% and 2.11% at December 31, 2013 and 2012, respectively)
Debt Instrument [Line Items]
Unsecured debt	$ 10,000,000	$ 10,000,000
Debt, face amount	$ 10,000,000
Interest rate at period end	2.31%	2.04%
Parent Company [Member] | LIBOR Plus 1.80% debentures, due April 19, 2035 with quarterly interest payments and principal to be paid at maturity (rate of 2.04% and 2.11% at December 31, 2013 and 2012, respectively) | LIBOR [Member]
Debt Instrument [Line Items]
Basis spread on variable rate	1.80%	1.80%
Synovus Bank [Member]
Debt Instrument [Line Items]
Long-term debt	$ 1,226,708,000	$ 1,377,053,000
Synovus Bank [Member] | FHLB Advances [Member]
Debt Instrument [Line Items]
FHLB advances with interest and principal payments due at various maturity dates through 2018	$ 1,225,000,000	$ 1,375,271,000
Stated percentage rate range, minimum	0.29%
Stated percentage rate range, maximum	0.95%
Weighted average interest rate	0.46%	0.54%
Synovus Bank [Member] | Other Notes Payable and Capital Leases [Member]
Debt Instrument [Line Items]
Other notes payable and capital leases with interest and principal payments due at various maturity dates through 2031	$ 1,708,000	$ 1,782,000
Weighted average interest rate	1.59%	1.59%