Mergers and Acquisitions-Additional Information (Details) $ in Thousands				12 Months Ended
	Oct. 20, 2015 USD ($)	Jul. 01, 2015 USD ($) branch shares	Sep. 01, 2013 USD ($) shares	Dec. 31, 2015 USD ($) branch	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Aug. 31, 2013 branch
Business Acquisition [Line Items]
Goodwill				$ 445,871	$ 274,706	$ 276,100
Other intangible assets, net				$ 28,811	$ 22,624
Variable interest rate of derivatives, description				the three-month LIBOR plus pre-determined spread
KeyWorth Bank
Business Acquisition [Line Items]
Total Purchase Price	$ 58,700
Equity conversion ratio	0.4494
Number of offices in operation | branch				6
Total net assets acquired				$ 407,782
Borrowings				252,092
KeyWorth Bank | Core deposit intangible
Business Acquisition [Line Items]
Deposits assumed				$ 355,117
Heritage Financial Group
Business Acquisition [Line Items]
Total Purchase Price		$ 295,380
Total net assets acquired		124,198
Borrowings		314,656
Business Combination, Consideration Transferred For Target's Stock Options		$ 5,915
Percentage of voting interests acquired (percent)		100.00%
Number of banking, mortgage, and investment offices (branches) | branch		48
Intangible assets		$ 183,438
Goodwill		171,182
Other intangible assets, net		$ 12,256
Heritage Financial Group | Core deposit intangible
Business Acquisition [Line Items]
Useful life (in years)		10 years
Heritage Financial Group | Common Stock
Business Acquisition [Line Items]
Shares issued to common shareholders (shares) | shares		8,635,879
First M&F
Business Acquisition [Line Items]
Total Purchase Price			$ 156,845
Shares issued to common shareholders (shares) | shares			6,175,576
Percentage of voting interests acquired (percent)			100.00%
Intangible assets			$ 115,159
Goodwill			90,127
Number of banking and insurance locations (branches) | branch							43
First M&F | Junior subordinated debentures
Business Acquisition [Line Items]
Borrowings			$ 30,928
Variable interest rate of derivatives, description			90-day LIBOR
Liabilities, fair value adjustment			$ 12,371
First M&F | Core deposit intangible
Business Acquisition [Line Items]
Useful life (in years)			10 years
Intangible acquired			$ 25,032
First M&F | 90-day LIBOR | Junior subordinated debentures
Business Acquisition [Line Items]
Basis spread on variable rate (percent)			1.33%