Goodwill And Other Intangible Assets (Summary of Finite-Lived Intangible Assets) (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016
Finite-Lived Intangible Assets [Line Items]
Total other intangible assets, net	$ 19,546	$ 21,851	$ 21,821
Core deposit intangibles | Community banking
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	37,272	37,272	34,998
Accumulated amortization	(23,632)	(21,614)	(19,654)
Net carrying amount	13,640	15,658	15,344
Customer list intangibles | Specialty finance
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	1,800	1,800	1,800
Accumulated amortization	(1,221)	(1,159)	(1,100)
Net carrying amount	579	641	700
Customer list and other intangibles | Wealth management
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	7,940	7,940	7,940
Accumulated amortization	(2,613)	(2,388)	(2,163)
Net carrying amount	$ 5,327	$ 5,552	$ 5,777