Acquisition - Additional Information (Detail) (CommerceFirst Bancorp, inc., USD $) In Millions, except Share data, unless otherwise specified	1 Months Ended
	Jun. 30, 2013	May 31, 2012
CommerceFirst Bancorp, inc.
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Business acquisition, percentage of common stock acquired		100.00%
Business acquisition percentage of common stock acquired in exchange of common stock		50.00%
Business acquisition, percentage of common stock acquired in exchange of cash		50.00%
Stock consideration, exchange ratio		0.8043
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares		732,054
Business Acquisition, Cost of Acquired Entity, Cash Paid		$ 12.4
Business acquisition, cash consideration Paid Per Share		$ 13.60
Business Acquisition, Purchase Price Allocation, Assets Acquired		188.0
Business Acquisition Purchase Price Allocation Loans Receivable		165.8
Business Acquisition, Purchase Price Allocation, Liabilities Assumed		170.6
Business Acquisition Purchase Price Allocation Liabilities Assumed Deposits		169.9
Business Acquisition, Purchase Price Allocation, Goodwill Amount		8.0
Goodwill, Translation and Purchase Accounting Adjustments	$ 0.6