Fair Value Measurements (Foreclosed Assets Remeasured and Reported at Fair Value) (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreclosed Assets Remeasured at Initial Recognition Carrying Value Of Foreclosed Assets Prior To Remeasurement	$ 756	$ 1,102	$ 6,388
Foreclosed Assets Remeasured at Initial Recognition Charge Offs Recognized In Allowance For Loan Losses	(3)	(169)	(285)
Fair Value of Foreclosed Assets Remeasured at Initial Recognition	753	933	6,103
Foreclosed Assets Remeasured Subsequent to Initial Recognition Carrying Value Of Foreclosed Assets Prior To Remeasurement	492	205	5,026
Foreclosed Assets Remeasured Subsequent to initial Recognition Write Downs Included In Other Non Interest Expense	(217)	(36)	(1,289)
Fair Value of Foreclosed Assets remeasured subsequent to initial recognition	$ 275	$ 169	$ 3,737