Deferred Tax Asets And Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Deferred Tax Assets:
Allowance for loan and lease losses	$ 17,132	$ 19,714
Employee benefits	1,505	1,454
Pension plan OCI	5,933	4,482
Deferred loan fees and costs	579	681
Non-qualified stock option expense	376	413
Losses on other real estate owned	756	313
Other than temporary impairment	323	269
Loan and deposit premium/discount	2,267	159
Depreciation	0	0
Reserve for recourse loans	199	120
Loss carryforward	88	0
Other	145	111
Gross deferred tax assets	29,304	27,716
Valuation allowance	(88)	0
Net deferred tax assets	29,216	27,716
Deferred Tax Liabilities:
Unrealized gains on investments available for sale	(13,436)	(13,270)
Pension plan costs	(2,644)	(3,267)
Depreciation	(704)	(900)
Intangible assets	(568)	(286)
Bond accretion	(109)	(167)
Other	(16)	(16)
Gross deferred tax liabilities	(17,477)	(17,906)
Net deferred tax asset	$ 11,739	$ 9,810