Assets and Liabilities Measured at Fair Value on Non-Recurring Basis (Detail) - Fair Value, Measurements, Nonrecurring - USD ($) $ in Thousands		Sep. 30, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Certain impaired loans	[1]	$ 2,605	$ 23,366
Other assets	[2]	9,873	15,916
Total		12,478	39,282
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets	[2]	9,873	15,916
Total		9,873	15,916
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Certain impaired loans	[1]	2,605	23,366
Total		$ 2,605	$ 23,366

[1] Represents the fair value of certain impaired loans, based on the value of the collateral.

[2] Represents the fair value of OREO, based on the appraised value of the collateral subsequent to its initial classification as OREO.