Credit Quality Assessment (Credit Quality of Loan Portfolio by Segment) (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Financing Receivable Recorded Investment [Line Items]
Non-accrual loans and leases	$ 30,495	$ 28,530
Loans and leases 90 days past due	1	0
Restructured loans and leases	6,419	5,497
Total non-performing loans and leases	36,915	34,027
Other real estate owned	2,619	3,195
Total non-performing assets	39,534	37,222
Commercial
Financing Receivable Recorded Investment [Line Items]
Non-accrual loans and leases	3,881	3,184
Loans and leases 90 days past due	0	0
Restructured loans and leases	1,479	710
Total non-performing loans and leases	5,360	3,894
Other real estate owned	39	39
Total non-performing assets	5,399	3,933
Leases
Financing Receivable Recorded Investment [Line Items]
Non-accrual loans and leases	0	0
Loans and leases 90 days past due	1	0
Restructured loans and leases	0	0
Total non-performing loans and leases	1	0
Other real estate owned	0	0
Total non-performing assets	1	0
Consumer
Financing Receivable Recorded Investment [Line Items]
Non-accrual loans and leases	1,621	1,668
Loans and leases 90 days past due	0	0
Restructured loans and leases	0	0
Total non-performing loans and leases	1,621	1,668
Other real estate owned	690	0
Total non-performing assets	2,311	1,668
Commercial Real Estate Portfolio Segment | Commercial Acquisition, Development and Construction
Financing Receivable Recorded Investment [Line Items]
Non-accrual loans and leases	194	2,464
Loans and leases 90 days past due	0	0
Restructured loans and leases	0	0
Total non-performing loans and leases	194	2,464
Other real estate owned	365	365
Total non-performing assets	559	2,829
Commercial Real Estate Portfolio Segment | Commercial Investor Real Estate
Financing Receivable Recorded Investment [Line Items]
Non-accrual loans and leases	8,609	8,156
Loans and leases 90 days past due	0	0
Restructured loans and leases	2,088	2,123
Total non-performing loans and leases	10,697	10,279
Other real estate owned	38	0
Total non-performing assets	10,735	10,279
Commercial Real Estate Portfolio Segment | Commercial Owner Occupied Real Estate
Financing Receivable Recorded Investment [Line Items]
Non-accrual loans and leases	7,932	8,941
Loans and leases 90 days past due	0	0
Restructured loans and leases	240	0
Total non-performing loans and leases	8,172	8,941
Other real estate owned	0	0
Total non-performing assets	8,172	8,941
Residential Real Estate Portfolio Segment | Residential Mortgage
Financing Receivable Recorded Investment [Line Items]
Non-accrual loans and leases	7,488	3,012
Loans and leases 90 days past due	0	0
Restructured loans and leases	2,612	2,664
Total non-performing loans and leases	10,100	5,676
Other real estate owned	1,487	1,408
Total non-performing assets	11,587	7,084
Residential Real Estate Portfolio Segment | Residential Construction
Financing Receivable Recorded Investment [Line Items]
Non-accrual loans and leases	770	1,105
Loans and leases 90 days past due	0	0
Restructured loans and leases	0	0
Total non-performing loans and leases	770	1,105
Other real estate owned	0	1,383
Total non-performing assets	$ 770	$ 2,488