Loans and Allowance for Loan Losses - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013		Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Deferred loan fee income	$ 87,000,000				$ 89,000,000
Loans modified in TDRs	23,232,000				22,433,000
Unfunded commitments available for funding	300,000
Loans modified in TDRs during the period	12,133,000	[1]	1,375,000	[1]
Forgiveness Of Principal
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified in TDRs during the period	2,800,000
Payment Deferrals Granted
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified in TDRs during the period	$ 9,300,000		$ 1,400,000

[1] the three months ended March 31, 2014 or March 31, 2013.