Summary of Significant Accounting Policies - Additional Information (Detail) shares in Millions		12 Months Ended
	Jun. 19, 2015 shares	Dec. 31, 2015 USD ($) shareholder shares	Dec. 31, 2014 USD ($) SecurityLoan shares	Dec. 31, 2013 USD ($) shares
Summary Of Significant Accounting Policies [Line Items]
Shareholders require to qualify REIT | shareholder		100
Percentage of preferred stock issued by each REIT - less than		20.00%
Cash reserve or deposits		$ 304,000,000	$ 45,500,000
Allowance for loan losses		$ 106,178,000	$ 102,353,000	$ 113,617,000
Look-back period for establishing allowance for credit losses		4 years	3 years
OREO and repossessed assets total		$ 19,000,000	$ 24,700,000
Foreclosed assets acquired in FDIC-assisted transactions		5,000,000	9,200,000
Foreclosed residential real estate properties		7,000,000
Properties for which formal foreclosure proceedings are in process		12,300,000
FDIC loss-share receivable		$ 8,300,000	$ 13,800,000
Anti-dilutive common stock options and warrants | shares		4.7	6.2	6.7
Trust preferred securities [Member]
Summary Of Significant Accounting Policies [Line Items]
Impairment charge part of combined amortized cost of the securities		$ 0	$ 0	$ 0
Series A Preferred Stock [Member]
Summary Of Significant Accounting Policies [Line Items]
Stock issued, shares | shares	4.6	4.6
First United Bancorp, Inc. [Member] | Park Avenue Bank Acquisition [Member]
Summary Of Significant Accounting Policies [Line Items]
FDIC loss share coverage percentage up to first tranche		95.00%
First United Bancorp, Inc. [Member] | Liberty Pointe Bank Acquisition [Member]
Summary Of Significant Accounting Policies [Line Items]
FDIC loss share coverage percentage up to first tranche		80.00%
First United Bancorp, Inc. [Member] | Old Harbor Bank [Member]
Summary Of Significant Accounting Policies [Line Items]
FDIC loss share coverage percentage up to first tranche		70.00%
First United Bancorp, Inc. [Member] | The Bank Of Miami [Member]
Summary Of Significant Accounting Policies [Line Items]
FDIC loss share coverage percentage up to first tranche		80.00%
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Premises and equipment, useful life		3 years
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Premises and equipment, useful life		40 years
Commercial and industrial [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for loan losses		$ 48,767,000	43,676,000	$ 51,551,000
Loans evaluated for impairment		250,000
PCI Loans [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for loan losses		$ 0	200,000
Non-Performing Commercial Real Estate [Member]
Summary Of Significant Accounting Policies [Line Items]
Loans held for sale			$ 7,100,000
Commercial loans [Member] | Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of days past due of loans to be full or partial charged-off		90 days
Commercial loans [Member] | Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of days past due of loans to be full or partial charged-off		120 days
Residential loans and home equity loans [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of days past due of loans to be full or partial charged-off		120 days
Automobile loans [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of days past due of loans to be fully charged-off		120 days
Unsecured consumer loans [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of days past due of loans to be fully charged-off		150 days
Non-Performing Loans [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of loans held for sale (in loan) | SecurityLoan			1