Loans and Leases (Loan Portfolio Segment Balances) (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	$ 3,127,392,000	$ 2,784,266,000
Residential Mortgage | Residential Real Estate Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	717,886,000	618,381,000
Residential Construction | Residential Real Estate Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	136,741,000	129,177,000
Commercial Owner Occupied Real Estate | Commercial Real Estate Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	611,061,000	592,823,000
Commercial Investor Real Estate | Commercial Real Estate Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	640,193,000	552,178,000
Commercial Acquisition, Development and Construction | Commercial Real Estate Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	205,124,000	160,696,000
Commercial Business
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	390,781,000	356,651,000
Leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	54,000	703,000
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	$ 425,552,000	$ 373,657,000