Mergers and Acquisitions - Pro Forma Combined Condensed Consolidated Financial Information (Details) - Heritage Financial Group - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Business Acquisition [Line Items]
Interest income	$ 225,985	$ 222,055
Interest expense	16,494	22,302
Net interest income	209,491	199,753
Provision for loan and lease losses	3,300	6,401
Noninterest income	103,888	85,774
Noninterest expense	238,947	201,166
Income before income taxes	71,132	77,960
Income taxes	22,597	24,106
Net income	$ 48,535	$ 53,854
Earnings per share:
Basic (usd per share)	$ 1.12	$ 1.34
Diluted (usd per share)	$ 1.12	$ 1.34