Loans Receivable and Allowance for Loan Losses - Restructured Loans Included in Nonaccrual Status were Modified as Troubled Debt Restructurings within Previous 12 Months and for which There was Payment Default (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014 Contract	Sep. 30, 2013 Contract	Sep. 30, 2014 Contract	Sep. 30, 2013 Contract
Financing Receivable, Modifications [Line Items]
Number of Contracts	3	0	4	0
Recorded Investment	$ 724	$ 0	$ 4,219	$ 0
Commercial Real Estate [Member] | Acquisition and Development [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	1	0	1	0
Recorded Investment	544	0	544	0
Commercial Real Estate [Member] | Non-Owner Occupied Residential [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts			1	0
Recorded Investment			3,495	0
Residential Mortgage [Member] | First Lien [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	2	0	2	0
Recorded Investment	$ 180	$ 0	$ 180	$ 0