Other Comprehensive Income (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Pre-Tax Amount
Change in net unrealized gains/(losses) on securities available-for-sale		$ 5,177	$ (2,032)	$ 4,288	$ 7,844
Reclassification adjustment for net (gains)/losses on securities available-for-sale included in net income	[1]	0	0	34	(41)
Adjustment to funded status of employee benefit plans		647	269	1,839	692
Other Comprehensive Income/(Loss)		5,824	(1,763)	6,161	8,495
Tax (Expense) Benefit
Change in net unrealized gains/(losses) on securities available-for-sale		(1,812)	712	(1,501)	(2,746)
Reclassification adjustment for net (gains)/losses on securities available-for-sale included in net income	[1]	0	0	(12)	15
Adjustment to funded status of employee benefit plans		(227)	(94)	(551)	(242)
Other Comprehensive (Loss)/Income		(2,039)	618	(2,064)	(2,973)
Net of Tax Amount
Change in net unrealized gains/(losses) on securities available-for-sale		3,365	(1,320)	2,787	5,098
Reclassification adjustment for net (gains)/losses on securities available-for-sale included in net income	[1]	0	0	22	(26)
Adjustment to funded status of employee benefit plans		420	175	1,288	450
Other Comprehensive Income/(Loss)		$ 3,785	$ (1,145)	$ 4,097	$ 5,522

[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.