Business Combinations (Details) $ / shares in Units, $ in Millions			3 Months Ended
	May. 27, 2015 USD ($) Branch $ / shares shares	Nov. 01, 2014 USD ($) Branch shares	Mar. 31, 2015 USD ($)
CNL Bancshares, Inc.
Business Acquisition [Line Items]
Assets acquired	$ 1,400.0
Loans acquired	843.0
Deposits acquired	$ 1,100.0
Number of branches acquired (in branch) | Branch	16
Common stock issued per share held (in shares) | shares	0.75
Value of transaction based on closing stock price	$ 207.0
Consideration given in stock	$ 16.2
CNL Bancshares, Inc. | Minimum
Business Acquisition [Line Items]
Share price | $ / shares	$ 8.80
CNL Bancshares, Inc. | Maximum
Business Acquisition [Line Items]
Share price | $ / shares	$ 10.13
First United Bancorp, Inc.
Business Acquisition [Line Items]
Assets acquired		$ 1,700.0
Loans acquired		1,200.0
Deposits acquired		$ 1,400.0
Number of branches acquired (in branch) | Branch		20
Common stock issued per share held (in shares) | shares		0.89
Value of transaction based on closing stock price		$ 300.0
Shares issued in acquisition | shares		30,700,000
Cash consideration paid		$ 8.9
Increase in goodwill			$ 1.6