Goodwill And Other Intangible Assets (Other Intangible Assets) (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Amortization during the period	$ 521	$ 540
Core Deposits Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	12,378		$ 12,378
Accumulated amortization	11,899		11,420
Net carrying amount	479		958
Amortization during the period	$ 479		$ 1,995
Weighted average remaining life (in years)	3 months		6 months
Client Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 1,459		$ 1,459
Accumulated amortization	1,190		1,148
Net carrying amount	269		311
Amortization during the period	$ 42		$ 166
Weighted average remaining life (in years)	3 years 9 months		4 years 1 month