Disclosures about Fair Value of Financial Instruments - Statement of Changes in Level 3 Assets and Liabilities Measured at Fair Value on a Recurring Basis (Detail) (Significant Unobservable Inputs (Level 3), USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Balance, Beginning of the Period		$ 0
Issuances		240
Transfer from Level 2 to Level 3		3,173
Recoveries		(1,463)
Sales		(1,013)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		(697)
Balance, End of the Period		240
Loans Held for Sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Balance, Beginning of the Period		0
Issuances		0
Transfer from Level 2 to Level 3		3,173
Recoveries		(1,463)
Sales		(1,013)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		(697)
Balance, End of the Period		0
Residential Mortgage Loan Commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Balance, Beginning of the Period	240	0
Issuances	235	240
Settlements	(432)
Transfer from Level 2 to Level 3		0
Recoveries		0
Sales		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		0
Balance, End of the Period	$ 43	$ 240