Income Taxes - Additional information - (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Income Taxes
Unrecognized tax benefits	$ 0.0
Accrued interest and penalties	0.0
Peoples
Income Taxes
Operating loss carryforwards	7.5
Annual limitation on operating loss carryforwards	1.5
Savannah Bancorp ("SAVB")
Income Taxes
Operating loss carryforwards	17.0
Annual limitation on operating loss carryforwards	2.0
Park Sterling Corporation
Income Taxes
Operating loss carryforwards	5.8
RBIL carryforwards	15.0
Annual limitations on RBIL carryforward	1.1
Annual limitation on operating loss carryforwards	3.3
Federal
Income Taxes
Operating loss carryforwards	30.3	$ 27.9
State
Income Taxes
Operating loss carryforwards	88.5	$ 72.1
Valuation allowance relating to operating loss carryforwards	$ 3.0