Loans and Loans Held for Sale - Restructured Loans for Periods Stated (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) loan	Dec. 31, 2014 USD ($) loan
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	60	44
Pre-Modification Outstanding Recorded Investment	$ 8,290	$ 4,949
Post-Modification Outstanding Recorded Investment	6,338	4,777
Increase (Decrease) Financing Receivable Modifications Difference In Recorded Investments	$ (1,952)	$ (172)
Principal Deferral
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	8	6
Pre-Modification Outstanding Recorded Investment	$ 3,512	$ 2,372
Post-Modification Outstanding Recorded Investment	2,204	2,321
Increase (Decrease) Financing Receivable Modifications Difference In Recorded Investments	$ (1,308)	$ (51)
Interest Rate Reduction and Maturity Date Extension
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	4	2
Pre-Modification Outstanding Recorded Investment	$ 410	$ 96
Post-Modification Outstanding Recorded Investment	406	95
Increase (Decrease) Financing Receivable Modifications Difference In Recorded Investments	$ (4)	$ (1)
Maturity Date Extension
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	17	7
Pre-Modification Outstanding Recorded Investment	$ 3,312	$ 1,368
Post-Modification Outstanding Recorded Investment	2,922	1,322
Increase (Decrease) Financing Receivable Modifications Difference In Recorded Investments	$ (390)	$ (46)
Chapter 7 Bankruptcy
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	31	29
Pre-Modification Outstanding Recorded Investment	$ 1,056	$ 1,113
Post-Modification Outstanding Recorded Investment	806	1,039
Increase (Decrease) Financing Receivable Modifications Difference In Recorded Investments	$ (250)	$ (74)
Commercial Real Estate | Principal Deferral
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	2	4
Pre-Modification Outstanding Recorded Investment	$ 2,851	$ 1,991
Post-Modification Outstanding Recorded Investment	1,841	1,965
Increase (Decrease) Financing Receivable Modifications Difference In Recorded Investments	$ (1,010)	$ (26)
Commercial Real Estate | Maturity Date Extension
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	3
Pre-Modification Outstanding Recorded Investment	$ 438
Post-Modification Outstanding Recorded Investment	427
Increase (Decrease) Financing Receivable Modifications Difference In Recorded Investments	$ (11)
Commercial and Industrial | Principal Deferral
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	6	2
Pre-Modification Outstanding Recorded Investment	$ 661	$ 381
Post-Modification Outstanding Recorded Investment	363	356
Increase (Decrease) Financing Receivable Modifications Difference In Recorded Investments	$ (298)	$ (25)
Commercial and Industrial | Maturity Date Extension
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	2
Pre-Modification Outstanding Recorded Investment	$ 824
Post-Modification Outstanding Recorded Investment	728
Increase (Decrease) Financing Receivable Modifications Difference In Recorded Investments	$ (96)
Commercial Construction | Maturity Date Extension
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	3	1
Pre-Modification Outstanding Recorded Investment	$ 1,434	$ 1,019
Post-Modification Outstanding Recorded Investment	1,432	974
Increase (Decrease) Financing Receivable Modifications Difference In Recorded Investments	$ (2)	$ (45)
Residential Mortgage | Interest Rate Reduction and Maturity Date Extension
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	1
Pre-Modification Outstanding Recorded Investment	$ 207
Post-Modification Outstanding Recorded Investment	205
Increase (Decrease) Financing Receivable Modifications Difference In Recorded Investments	$ (2)
Residential Mortgage | Maturity Date Extension
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	8
Pre-Modification Outstanding Recorded Investment	$ 545
Post-Modification Outstanding Recorded Investment	265
Increase (Decrease) Financing Receivable Modifications Difference In Recorded Investments	$ (280)
Residential Mortgage | Chapter 7 Bankruptcy
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	7	9
Pre-Modification Outstanding Recorded Investment	$ 428	$ 651
Post-Modification Outstanding Recorded Investment	226	634
Increase (Decrease) Financing Receivable Modifications Difference In Recorded Investments	$ (202)	$ (17)
Home Equity | Interest Rate Reduction and Maturity Date Extension
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	3	2
Pre-Modification Outstanding Recorded Investment	$ 203	$ 96
Post-Modification Outstanding Recorded Investment	201	95
Increase (Decrease) Financing Receivable Modifications Difference In Recorded Investments	$ (2)	$ (1)
Home Equity | Maturity Date Extension
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	1	6
Pre-Modification Outstanding Recorded Investment	$ 71	$ 349
Post-Modification Outstanding Recorded Investment	70	348
Increase (Decrease) Financing Receivable Modifications Difference In Recorded Investments	$ (1)	$ (1)
Home Equity | Chapter 7 Bankruptcy
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	23	15
Pre-Modification Outstanding Recorded Investment	$ 619	$ 432
Post-Modification Outstanding Recorded Investment	576	382
Increase (Decrease) Financing Receivable Modifications Difference In Recorded Investments	$ (43)	$ (50)
Installment and Other Consumer | Chapter 7 Bankruptcy
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	1	5
Pre-Modification Outstanding Recorded Investment	$ 9	$ 30
Post-Modification Outstanding Recorded Investment	4	23
Increase (Decrease) Financing Receivable Modifications Difference In Recorded Investments	$ (5)	$ (7)