Other Comprehensive Income (Detail) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Pre-Tax Amount
Change in unrealized (losses)/gains on securities available-for-sale		$ (5,872)	$ 5,401	$ (889)	$ 9,876
Reclassification adjustment for net (gains)/losses on securities available-for-sale included in net income	[1]	34	(40)	34	(41)
Adjustment to funded status of employee benefit plans		463	211	1,192	423
Other Comprehensive (Loss)/Income		(5,375)	5,572	337	10,258
Tax (Expense) Benefit
Change in unrealized (losses)/ gains on securities available-for-sale		2,056	(1,891)	311	(3,457)
Reclassification adjustment for net (gains)/losses on securities available-for-sale included in net income	[1]	(12)	15	(12)	15
Adjustment to funded status of employee benefit plans		(162)	(74)	(324)	(148)
Other Comprehensive (Loss)/Income		1,882	(1,950)	(25)	(3,590)
Net of Tax Amount
Change in unrealized (losses)/ gains on securities available-for-sale		(3,816)	3,510	(578)	6,419
Reclassification adjustment for net (gains)/losses on securities available-for-sale included in net income	[1]	22	(25)	22	(26)
Adjustment to funded status of employee benefit plans		301	137	868	275
Other Comprehensive (Loss)/Income		$ (3,493)	$ 3,622	$ 312	$ 6,668

[1] Reclassification adjustments are comprised of realized security gains. The gains have been reclassified out of accumulated other comprehensive income (loss) and have affected certain lines in the Consolidated Statements of Comprehensive Income as follows; the pre-tax amount is included in securities gains-net, the tax expense amount is included in the provision for income taxes and the net of tax amount is included in net income.