Loans and Leases (Loan Portfolio Segment Balances) (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	$ 3,164,706,000	$ 3,127,392,000
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	385,452,000	390,781,000
Leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	36,000	54,000
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	428,531,000	425,552,000
Commercial Real Estate Portfolio Segment [Member] | Commercial Owner Occupied Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	618,846,000	611,061,000
Commercial Real Estate Portfolio Segment [Member] | Commercial Investor Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	668,931,000	640,193,000
Commercial Real Estate Portfolio Segment [Member] | Commercial Acquisition, Development and Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	203,731,000	205,124,000
Residential Real Estate Portfolio Segment [Member] | Residential Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	728,858,000	717,886,000
Residential Real Estate Portfolio Segment [Member] | Residential Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	$ 130,321,000	$ 136,741,000