Loans and Allowance for Credit Losses - Schedule of Troubled Debt Restructurings for which there was Payment Default (Detail) (Troubled Debt Restructurings that Subsequently Defaulted [Member], USD $) In Thousands, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2014 SecurityLoan	Dec. 31, 2013 SecurityLoan
Financing Receivable, Modifications [Line Items]
Number of Contracts	5	5
Recorded Investment	$ 234	$ 117
Commercial Loan [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	3	3
Recorded Investment	92	32
Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	2	2
Recorded Investment	$ 142	$ 85