Credit Quality of Loan Portfolio by Segment (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Financing Receivable, Recorded Investment [Line Items]
Non-accrual loans and leases	$ 55,567	$ 71,680
Loans and leases 90 days past due	604	577
Restructured loans and leases (accruing)	8,285	6,881
Total non-performing loans and leases	64,456	79,138
Total non-performing assets	74,009	83,569
Commercial Loan
Financing Receivable, Recorded Investment [Line Items]
Non-accrual loans and leases	4,583	7,226
Loans and leases 90 days past due	70
Restructured loans and leases (accruing)	2,475	1,866
Total non-performing loans and leases	7,128	9,092
Total non-performing assets	8,957	9,192
Leases
Financing Receivable, Recorded Investment [Line Items]
Non-accrual loans and leases	872	853
Loans and leases 90 days past due	96	2
Total non-performing loans and leases	968	855
Total non-performing assets	968	855
Consumer Loan
Financing Receivable, Recorded Investment [Line Items]
Non-accrual loans and leases	1,651	1,786
Loans and leases 90 days past due	5	165
Restructured loans and leases (accruing)	33	35
Total non-performing loans and leases	1,689	1,986
Total non-performing assets	1,689	1,986
Other Real Estate Owned
Financing Receivable, Recorded Investment [Line Items]
Other non performing assets	9,553	4,431
Other Real Estate Owned | Commercial Loan
Financing Receivable, Recorded Investment [Line Items]
Other non performing assets	1,829	100
Commercial Real Estate Portfolio Segment | Commercial Acquisition, Development and Construction
Financing Receivable, Recorded Investment [Line Items]
Non-accrual loans and leases	13,055	18,702
Loans and leases 90 days past due	342
Total non-performing loans and leases	13,397	18,702
Total non-performing assets	13,397	18,702
Commercial Real Estate Portfolio Segment | Commercial Investor Real Estate
Financing Receivable, Recorded Investment [Line Items]
Non-accrual loans and leases	13,327	16,963
Total non-performing loans and leases	13,327	16,963
Total non-performing assets	13,789	17,425
Commercial Real Estate Portfolio Segment | Commercial Owner Occupied Real Estate
Financing Receivable, Recorded Investment [Line Items]
Non-accrual loans and leases	15,146	14,709
Restructured loans and leases (accruing)	1,533	707
Total non-performing loans and leases	16,679	15,416
Total non-performing assets	21,248	15,689
Commercial Real Estate Portfolio Segment | Other Real Estate Owned | Commercial Investor Real Estate
Financing Receivable, Recorded Investment [Line Items]
Other non performing assets	462	462
Commercial Real Estate Portfolio Segment | Other Real Estate Owned | Commercial Owner Occupied Real Estate
Financing Receivable, Recorded Investment [Line Items]
Other non performing assets	4,569	273
Residential Real Estate Portfolio Segment | Residential Mortgage
Financing Receivable, Recorded Investment [Line Items]
Non-accrual loans and leases	2,600	5,722
Loans and leases 90 days past due	91	167
Restructured loans and leases (accruing)	4,244	3,579
Total non-performing loans and leases	6,935	9,468
Total non-performing assets	8,748	12,863
Residential Real Estate Portfolio Segment | Residential Construction
Financing Receivable, Recorded Investment [Line Items]
Non-accrual loans and leases	4,333	5,719
Loans and leases 90 days past due		243
Restructured loans and leases (accruing)		694
Total non-performing loans and leases	4,333	6,656
Total non-performing assets	5,213	6,857
Residential Real Estate Portfolio Segment | Other Real Estate Owned | Residential Mortgage
Financing Receivable, Recorded Investment [Line Items]
Other non performing assets	1,813	3,395
Residential Real Estate Portfolio Segment | Other Real Estate Owned | Residential Construction
Financing Receivable, Recorded Investment [Line Items]
Other non performing assets	$ 880	$ 201