Loans - Financing Receivables Modified as Troubled Debt Restructurings within Previous 12 Months for Payment Default (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013 Contract	Dec. 31, 2012 Contract	Dec. 31, 2011 Contract
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructurings That Subsequently Defaulted, Number of Contracts	9	7	6
Troubled Debt Restructurings That Subsequently Defaulted, Recorded Investment	$ 591	$ 1,677	$ 477
Residential: 1-4 family [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructurings That Subsequently Defaulted, Number of Contracts	9	6	5
Troubled Debt Restructurings That Subsequently Defaulted, Recorded Investment	591	677	438
Residential: Home equities [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructurings That Subsequently Defaulted, Number of Contracts			1
Troubled Debt Restructurings That Subsequently Defaulted, Recorded Investment			39
Commercial real estate: Other [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructurings That Subsequently Defaulted, Number of Contracts		1
Troubled Debt Restructurings That Subsequently Defaulted, Recorded Investment		$ 1,000