Loans and Allowance for Loan Losses (Details 3) (USD $)	Dec. 31, 2013	Jul. 26, 2013 FFCH Non-credit impaired	Dec. 31, 2012 Savannah Bancorp ("SAVB") Non-credit impaired	Dec. 31, 2013 Acquired loans	Dec. 31, 2012 Acquired loans	Dec. 31, 2013 Acquired loans Credit impaired	Dec. 31, 2012 Acquired loans Credit impaired	Dec. 31, 2013 Acquired loans Non-credit impaired	Dec. 31, 2012 Acquired loans Non-credit impaired	Jul. 26, 2013 Acquired loans FFCH	Dec. 13, 2012 Acquired loans Savannah Bancorp ("SAVB")	Apr. 24, 2012 Acquired loans Peoples Credit impaired	Jul. 26, 2013 Acquired loans Loans Impaired at Acquisition FFCH Credit impaired	Dec. 13, 2012 Acquired loans Loans Impaired at Acquisition Savannah Bancorp ("SAVB") Credit impaired	Apr. 24, 2012 Acquired loans Loans Impaired at Acquisition Peoples Credit impaired	Jul. 26, 2013 Acquired loans Loans Not Impaired at Acquisition FFCH Credit impaired	Dec. 13, 2012 Acquired loans Loans Not Impaired at Acquisition Savannah Bancorp ("SAVB") Credit impaired	Apr. 24, 2012 Acquired loans Loans Not Impaired at Acquisition Peoples Credit impaired
Contractual loan payments receivable, estimates of amounts not expected to be collected, other fair value adjustments and the resulting fair values of acquired loans
Contractual principal and interest						$ 1,700,129,000	$ 1,288,133,000			$ 873,151,000	$ 638,875,000	$ 306,963,000	$ 650,331,000	$ 155,582,000	$ 56,940,000	$ 222,820,000	$ 483,293,000	$ 250,023,000
Non-accretable difference						(222,091,000)	(140,671,000)			(150,420,000)	(46,952,000)	(37,797,000)	(125,701,000)	(37,492,000)	(21,237,000)	(24,719,000)	(9,460,000)	(16,560,000)
Cash flows expected to be collected						1,478,038,000	1,147,462,000			722,731,000	591,923,000	269,166,000	524,630,000	118,090,000	35,703,000	198,101,000	473,833,000	233,463,000
Accretable difference						(250,340,000)	(160,849,000)			(130,780,000)	(60,081,000)	(34,921,000)	(102,260,000)	(8,615,000)	(4,968,000)	(28,520,000)	(51,466,000)	(29,953,000)
Total acquired loans				1,227,698,000	986,613,000	1,227,698,000	986,613,000	1,598,051,000	73,215,000	591,951,000	531,842,000	234,245,000	422,370,000	109,475,000	30,735,000	169,581,000	422,367,000	203,510,000
Allowance for loan losses on acquired loans	0			(11,618,000)	(17,218,000)	(11,618,000)	(17,218,000)
Unpaid principal balance for acquired loans		1,670,000,000	69,500,000
Contractual principal		1,710,000,000	74,900,000
Fair value adjustment		$ 40,600,000	$ 5,400,000