Credit Quality Assessment (Recorded Investment with Respect to Impaired loans, Associated Allowance by Applicable Portfolio Segment and Principal Balance of Impaired Loans prior to Amounts Charged-off) (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	$ 14,208	$ 11,411	$ 12,217
Impaired loans without a specific allowance	14,719	18,008	20,306
Impaired loans	28,927	29,419	$ 32,523
Impaired Financing Receivable, Related Allowance	3,375	2,894
Unpaid principal balance in total impaired loans	42,461	42,185
Non Accrual Loans
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	12,536	9,104
Impaired loans without a specific allowance	5,035	8,676
Impaired loans	17,571	17,780
Restructuring | Accrual Loans
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	876	687
Impaired loans without a specific allowance	3,591	4,810
Impaired loans	4,467	5,497
Restructuring | Non Accrual Loans
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	796	1,620
Impaired loans without a specific allowance	6,093	4,522
Impaired loans	6,889	6,142
Commercial
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	2,200	1,468
Impaired loans without a specific allowance	3,073	2,426
Impaired loans	5,273	3,894
Impaired Financing Receivable, Related Allowance	1,318	788
Unpaid principal balance in total impaired loans	7,158	5,360
Commercial | Non Accrual Loans
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	1,168	473
Impaired loans without a specific allowance	974	1,115
Impaired loans	2,142	1,588
Commercial | Restructuring | Accrual Loans
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	876	687
Impaired loans without a specific allowance	701	23
Impaired loans	1,577	710
Commercial | Restructuring | Non Accrual Loans
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	156	308
Impaired loans without a specific allowance	1,398	1,288
Impaired loans	1,554	1,596
All Other
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	0	0
Impaired loans without a specific allowance	6,439	3,841
Impaired loans	6,439	3,841
Impaired Financing Receivable, Related Allowance	0	0
Unpaid principal balance in total impaired loans	7,154	4,126
All Other | Non Accrual Loans
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	0	0
Impaired loans without a specific allowance	2,750	0
Impaired loans	2,750	0
All Other | Restructuring | Accrual Loans
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	0	0
Impaired loans without a specific allowance	577	2,664
Impaired loans	577	2,664
All Other | Restructuring | Non Accrual Loans
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	0	0
Impaired loans without a specific allowance	3,112	1,177
Impaired loans	3,112	1,177
Commercial Real Estate Portfolio Segment | Commercial Acquisition, Development and Construction
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	58	1,330
Impaired loans without a specific allowance	136	1,134
Impaired loans	194	2,464
Impaired Financing Receivable, Related Allowance	58	741
Unpaid principal balance in total impaired loans	4,456	7,044
Commercial Real Estate Portfolio Segment | Commercial Acquisition, Development and Construction | Non Accrual Loans
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	58	1,330
Impaired loans without a specific allowance	0	0
Impaired loans	58	1,330
Commercial Real Estate Portfolio Segment | Commercial Acquisition, Development and Construction | Restructuring | Accrual Loans
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	0	0
Impaired loans without a specific allowance	0	0
Impaired loans	0	0
Commercial Real Estate Portfolio Segment | Commercial Acquisition, Development and Construction | Restructuring | Non Accrual Loans
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	0	0
Impaired loans without a specific allowance	136	1,134
Impaired loans	136	1,134
Commercial Real Estate Portfolio Segment | Commercial Investor Real Estate
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	7,791	2,364
Impaired loans without a specific allowance	2,650	7,915
Impaired loans	10,441	10,279
Impaired Financing Receivable, Related Allowance	1,489	541
Unpaid principal balance in total impaired loans	15,138	14,926
Commercial Real Estate Portfolio Segment | Commercial Investor Real Estate | Non Accrual Loans
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	7,791	2,288
Impaired loans without a specific allowance	518	5,792
Impaired loans	8,309	8,080
Commercial Real Estate Portfolio Segment | Commercial Investor Real Estate | Restructuring | Accrual Loans
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	0	0
Impaired loans without a specific allowance	2,073	2,123
Impaired loans	2,073	2,123
Commercial Real Estate Portfolio Segment | Commercial Investor Real Estate | Restructuring | Non Accrual Loans
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	0	76
Impaired loans without a specific allowance	59	0
Impaired loans	59	76
Commercial Real Estate Portfolio Segment | Commercial Owner Occupied Real Estate
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	4,159	6,249
Impaired loans without a specific allowance	2,421	2,692
Impaired loans	6,580	8,941
Impaired Financing Receivable, Related Allowance	510	824
Unpaid principal balance in total impaired loans	8,555	10,729
Commercial Real Estate Portfolio Segment | Commercial Owner Occupied Real Estate | Non Accrual Loans
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	3,519	5,013
Impaired loans without a specific allowance	793	1,769
Impaired loans	4,312	6,782
Commercial Real Estate Portfolio Segment | Commercial Owner Occupied Real Estate | Restructuring | Accrual Loans
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	0	0
Impaired loans without a specific allowance	240	0
Impaired loans	240	0
Commercial Real Estate Portfolio Segment | Commercial Owner Occupied Real Estate | Restructuring | Non Accrual Loans
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	640	1,236
Impaired loans without a specific allowance	1,388	923
Impaired loans	$ 2,028	$ 2,159