Fair Value Part 3 (Details) (USD $)	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013	Dec. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity	$ 1,156,790,000		$ 1,168,728,000
Net LHFI	6,120,352,000		5,732,433,000
FDIC indemnification asset	10,866,000	17,342,000	14,347,000	21,774,000
Deposits	9,860,366,000		9,859,902,000
Long-term FHLB advances	8,236,000		8,458,000
Subordinated notes	49,920,000		49,904,000
Junior subordinated debt securities	61,856,000		61,856,000
Nonfinancial Assets and Liabilities [Abstract]
Outstanding balances in impaired loans	30,500,000		31,600,000
Foreclosed assets measured at fair value	24,600,000	60,500,000
Allowance for possible loan losses, Charge-offs for foreclosed assets upon initial recognition	6,700,000	2,700,000
Foreclosed assets re-measured after initial recognition	25,900,000	28,300,000
Write-downs of allowance for foreclosed assets after initial recognition	3,300,000	4,400,000
Estimated fair value of financial instruments with immediate and shorter-term maturities maximum	90 days
BancTrust Financial Group, Inc. [Member]
Nonfinancial Assets and Liabilities [Abstract]
Foreclosed assets measured at fair value		40,100,000
Level 2 [Member] | Carrying Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and short-term investments	327,960,000		353,014,000
Securities held to maturity	1,156,790,000		1,168,728,000
Deposits	9,860,366,000		9,859,902,000
Short-term liabilities	620,543,000		317,972,000
Long-term FHLB advances	8,236,000		8,458,000
Subordinated notes	49,920,000		49,904,000
Junior subordinated debt securities	61,856,000		61,856,000
Level 2 [Member] | Estimate of Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and short-term investments	327,960,000		353,014,000
Securities held to maturity	1,162,871,000		1,150,833,000
Deposits	9,865,144,000		9,866,118,000
Short-term liabilities	620,543,000		317,972,000
Long-term FHLB advances	8,254,000		8,474,000
Subordinated notes	53,759,000		53,387,000
Junior subordinated debt securities	43,299,000		40,206,000
Level 3 [Member] | Carrying Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net LHFI	6,120,352,000		5,732,433,000
Net acquired loans	635,360,000		794,570,000
FDIC indemnification asset	10,866,000		14,347,000
Level 3 [Member] | Estimate of Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net LHFI	6,158,557,000		5,787,408,000
Net acquired loans	635,360,000		794,570,000
FDIC indemnification asset	$ 10,866,000		$ 14,347,000