Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended		12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating Loss Carryforwards [Line Items]
Net deferred tax assets	$ 60,818,000		$ 60,818,000	$ 60,274,000
U.S. federal tax rate			35.00%	35.00%	35.00%
Deferred Tax Assets Related to State Net Operating Losses	6,600,000		$ 6,600,000
Deferred Tax Assets, Operating Loss Carryforwards, Domestic	28,089,000		28,089,000	$ 33,507,000
Deferred Tax Assets, Tax Credit Carryforwards, Alternative Minimum Tax	4,261,000		4,261,000	3,355,000
Deferred Tax Assets, Unrealized Losses on Available-for-Sale Securities, Gross	4,616,000		4,616,000	3,906,000
New Accounting Pronouncement or Change In Accounting Principle Effect Of Income Tax Expense Benefit	400,000	$ 400,000
Affordable Housing Tax Credits and Other Tax Benefits, Amount			32,000	$ 39,000	$ 67,000
Amortization Method Qualified Affordable Housing Project Investments, Amortization			39,000
Affordable Housing Program Obligation	10,000,000		10,000,000
Affordable Housing Program Obligation Unfunded	8,300,000		8,300,000
Floridian Financial Group, Inc [Member]
Operating Loss Carryforwards [Line Items]
Net deferred tax assets	13,300,000		13,300,000
Deferred Tax Assets, Operating Loss Carryforwards, Domestic	15,600,000		15,600,000
Deferred Tax Assets, Tax Credit Carryforwards, Alternative Minimum Tax	209,000		209,000
Minimum [Member]
Operating Loss Carryforwards [Line Items]
Annual income before taxes			4,300,000
U.S. Federal [Member]
Operating Loss Carryforwards [Line Items]
Net deferred tax assets	48,000,000		$ 48,000,000
U.S. Federal [Member] | Maximum [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carry forwards Expiration Period			2032
U.S. Federal [Member] | Minimum [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carry forwards Expiration Period			2029
State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Net deferred tax assets	$ 12,800,000		$ 12,800,000
State and Local Jurisdiction [Member] | Maximum [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carry forwards Expiration Period			2034
State and Local Jurisdiction [Member] | Minimum [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carry forwards Expiration Period			2028