Assets and Liabilities Measured at Fair Value on Non-Recurring Basis (Detail) - Fair Value, Measurements, Nonrecurring - USD ($) $ in Thousands		Jun. 30, 2018		Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Certain impaired loans		$ 42,738	[1]	$ 45,837	[2]
Other assets	[3]			4,357
Total		42,738		50,194
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Certain impaired loans		42,738	[1]	45,837	[2]
Other assets	[3]			4,357
Total		$ 42,738		$ 50,194

[1] Represents the fair value of impaired loans based on the value of the collateral and repossessed assets, based on the appraised value of the collateral subsequent to its initial classification as repossessed assets.

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

[3] Represents the fair value of repossessed assets, based on the appraised value of the collateral subsequent to its initial classification as repossessed assets.