Activity in Allowance for Loan and Lease Losses by Respective Loan Portfolio Segment (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of year	$ 42,957	$ 49,426	$ 62,135
Provision (credit)	(1,084)	3,649
Charge-offs	(11,165)	(12,804)
Loan and lease recoveries	(8,058)	(2,686)	(2,368)
Net charge-offs	3,107	10,118	14,137
Balance at period end	38,766	42,957	49,426
Total loans and leases	2,784,266	2,531,128
Allowance for loans and leases to total loans and leases ratio	1.39%	1.70%
Balance of loans specifically evaluated for impairment	32,523	48,773
Allowance for loans specifically evaluated for impairment	3,058	5,149	7,791
Specific allowance to specific loans ratio	9.40%	10.56%
Balance of loans collectively evaluated	2,751,743	2,482,355
Allowance for loans collectively evaluated	35,708	37,808	41,635
Collective allowance to collective loans ratio	1.30%	1.52%
Commercial Business
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of year	6,495	6,727
Provision (credit)	1,910	(758)
Charge-offs	(2,915)	(1,022)
Loan and lease recoveries	818	1,548
Net charge-offs	(2,097)	526
Balance at period end	6,308	6,495
Total loans and leases	356,651	346,708
Allowance for loans and leases to total loans and leases ratio	1.77%	1.87%
Balance of loans specifically evaluated for impairment	5,608	8,984
Allowance for loans specifically evaluated for impairment	849	2,597
Specific allowance to specific loans ratio	15.14%	28.91%
Balance of loans collectively evaluated	351,043	337,724
Allowance for loans collectively evaluated	5,459	3,898
Collective allowance to collective loans ratio	1.56%	1.15%
Commercial Acquisition, Development and Construction
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans and leases	160,696	151,933
Commercial Investor Real Estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans and leases	552,178	456,888
Commercial Owner Occupied Real Estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans and leases	592,823	571,510
Leases
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of year	332	795
Provision (credit)	(326)	(478)
Charge-offs	0	(8)
Loan and lease recoveries	10	23
Net charge-offs	10	15
Balance at period end	16	332
Total loans and leases	703	3,421
Allowance for loans and leases to total loans and leases ratio	2.28%	9.70%
Balance of loans collectively evaluated	703	3,421
Allowance for loans collectively evaluated	16	332
Collective allowance to collective loans ratio	2.28%	9.70%
Consumer
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of year	3,846	4,873
Provision (credit)	1,951	44
Charge-offs	(1,853)	(1,298)
Loan and lease recoveries	198	227
Net charge-offs	(1,655)	(1,071)
Balance at period end	4,142	3,846
Total loans and leases	373,657	356,990
Allowance for loans and leases to total loans and leases ratio	1.11%	1.08%
Balance of loans specifically evaluated for impairment	29	31
Balance of loans collectively evaluated	373,628	356,959
Allowance for loans collectively evaluated	4,142	3,846
Collective allowance to collective loans ratio	1.11%	1.08%
Residential Mortgage
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans and leases	618,381	523,364
Residential Construction
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans and leases	129,177	120,314
Commercial Real Estate Portfolio Segment | Commercial Acquisition, Development and Construction
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of year	4,737	6,664
Provision (credit)	(3,978)	826
Charge-offs	(85)	(3,281)
Loan and lease recoveries	3,080	528
Net charge-offs	2,995	(2,753)
Balance at period end	3,754	4,737
Total loans and leases	160,696	151,933
Allowance for loans and leases to total loans and leases ratio	2.34%	3.12%
Balance of loans specifically evaluated for impairment	4,128	6,332
Allowance for loans specifically evaluated for impairment	1,031	0
Specific allowance to specific loans ratio	24.98%	0.00%
Balance of loans collectively evaluated	156,568	145,601
Allowance for loans collectively evaluated	2,723	4,737
Collective allowance to collective loans ratio	1.74%	3.25%
Commercial Real Estate Portfolio Segment | Commercial Investor Real Estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of year	9,583	8,248
Provision (credit)	1,100	4,928
Charge-offs	(4,774)	(3,690)
Loan and lease recoveries	3,354	97
Net charge-offs	(1,420)	(3,593)
Balance at period end	9,263	9,583
Total loans and leases	552,178	456,888
Allowance for loans and leases to total loans and leases ratio	1.68%	2.10%
Balance of loans specifically evaluated for impairment	7,654	11,843
Allowance for loans specifically evaluated for impairment	126	774
Specific allowance to specific loans ratio	1.65%	6.54%
Balance of loans collectively evaluated	544,524	445,045
Allowance for loans collectively evaluated	9,137	8,809
Collective allowance to collective loans ratio	1.68%	1.98%
Commercial Real Estate Portfolio Segment | Commercial Owner Occupied Real Estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of year	6,997	7,329
Provision (credit)	(874)	804
Charge-offs	(240)	(1,174)
Loan and lease recoveries	425	38
Net charge-offs	185	(1,136)
Balance at period end	6,308	6,997
Total loans and leases	592,823	571,510
Allowance for loans and leases to total loans and leases ratio	1.06%	1.22%
Balance of loans specifically evaluated for impairment	7,111	15,184
Allowance for loans specifically evaluated for impairment	426	598
Specific allowance to specific loans ratio	5.99%	3.94%
Balance of loans collectively evaluated	585,712	556,326
Allowance for loans collectively evaluated	5,882	6,399
Collective allowance to collective loans ratio	1.00%	1.15%
Residential Real Estate Portfolio Segment | Residential Mortgage
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of year	8,522	10,583
Provision (credit)	329	(167)
Charge-offs	(1,194)	(2,107)
Loan and lease recoveries	162	213
Net charge-offs	(1,032)	(1,894)
Balance at period end	7,819	8,522
Total loans and leases	618,381	523,364
Allowance for loans and leases to total loans and leases ratio	1.26%	1.63%
Balance of loans specifically evaluated for impairment	6,141	4,528
Allowance for loans specifically evaluated for impairment	626	713
Specific allowance to specific loans ratio	10.19%	15.75%
Balance of loans collectively evaluated	612,240	518,836
Allowance for loans collectively evaluated	7,193	7,809
Collective allowance to collective loans ratio	1.17%	1.51%
Residential Real Estate Portfolio Segment | Residential Construction
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of year	2,445	4,207
Provision (credit)	(1,196)	(1,550)
Charge-offs	(104)	(224)
Loan and lease recoveries	11	12
Net charge-offs	(93)	(212)
Balance at period end	1,156	2,445
Total loans and leases	129,177	120,314
Allowance for loans and leases to total loans and leases ratio	0.89%	2.03%
Balance of loans specifically evaluated for impairment	1,852	1,871
Allowance for loans specifically evaluated for impairment	0	467
Specific allowance to specific loans ratio	0.00%	24.96%
Balance of loans collectively evaluated	127,325	118,443
Allowance for loans collectively evaluated	$ 1,156	$ 1,978
Collective allowance to collective loans ratio	0.91%	1.67%