Fair Values Of Assets And Liabilities (Summary Of Assets Measured At Fair Value On A Nonrecurring Basis) (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans—collateral based	$ 90,540	$ 90,540	$ 101,255	$ 113,027
Fair Value Losses Recognized, Impaired loans—collateral based	4,635	10,865
Fair Value Losses Recognized, Other real estate owned	1,237	4,617
Fair Value Losses Recognized, Total	5,872	15,482
Fair Value, Measurements, Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans—collateral based	64,614	64,614
Other real estate owned	45,449	45,449
Total	110,063	110,063
Fair Value, Measurements, Nonrecurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans—collateral based	0	0
Other real estate owned	0	0
Total	0	0
Fair Value, Measurements, Nonrecurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans—collateral based	0	0
Other real estate owned	0	0
Total	0	0
Fair Value, Measurements, Nonrecurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans—collateral based	64,614	64,614
Other real estate owned	45,449	45,449
Total	$ 110,063	$ 110,063