Other Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Pre-Tax Amount
Change in net unrealized gains/(losses) on securities available-for-sale	$ 9,033	$ 4,983
Adjustment to funded status of employee benefit plans	3,800	729
Other Comprehensive Income/(Loss)	12,833	5,712
Tax (Expense) Benefit
Change in net unrealized gains/(losses) on securities available-for-sale	(3,162)	(1,745)
Adjustment to funded status of employee benefit plans	(1,330)	(162)
Other Comprehensive (Loss)/Income	(4,492)	(1,907)
Net of Tax Amount
Change in net unrealized gains/(losses) on securities available-for-sale	5,871	3,238
Adjustment to funded status of employee benefit plans	2,470	567
Other Comprehensive Income/(Loss)	$ 8,341	$ 3,805