Commitments and Contingencies - Off-balance Sheet Financial Instruments (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013
Commitments to Extend Credit [Member]
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]
Off-balance Sheet Risks, Amount, Liability	$ 533,364
Performance Letters Of Credit [Member]
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]
Off-balance Sheet Risks, Amount, Liability	16,786
Financial Standby Letters of Credit [Member]
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]
Off-balance Sheet Risks, Amount, Liability	25,315
Other Letters Of Credit [Member]
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]
Off-balance Sheet Risks, Amount, Liability	$ 197