Mergers and Acquisitions - (Details) $ in Thousands	Nov. 30, 2017 USD ($) shares	Jan. 03, 2017 USD ($) shares	Aug. 21, 2015 USD ($) location item	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Mergers and Acquisitions
Deferred tax assets				$ 85,041	$ 76,447
Deferred Tax Liabilities, Gross				$ 36,119	$ 43,322
Bank of America
Mergers and Acquisitions
Number of full service branches | item			12
Total purchase price			$ 25,019
Deferred tax assets			0
Deferred Tax Liabilities, Gross			$ 0
Bank of America | Georgia Branch
Mergers and Acquisitions
Number of full service branches | location			1
Bank of America | South Carolina Branch
Mergers and Acquisitions
Number of full service branches | location			12
Southeastern Bank Financial
Mergers and Acquisitions
Fixed exchange ratio for shares issued (in shares)		0.7307
Common stock shares issued | shares		4,978,338
Total purchase price		$ 435,115
Value of stock options		$ 490
Park Sterling Corporation
Mergers and Acquisitions
Fixed exchange ratio for shares issued (in shares)	0.14
Common stock shares issued | shares	7,480,343
Total purchase price	$ 692,959
Value of stock options	$ 4,305