Tax Effects on Other Comprehensive Income (Loss) - Tax Effects of Components of Other Comprehensive Income (Loss) (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Pre-Tax Amount
Net change in unrealized (losses) gains on securities available-for-sale, Pre-Tax Amount	$ (16,928)	$ 4,097	$ 6,702
Net available-for-sale securities (gains) losses reclassified into earnings, Pre-Tax Amount	(5)	(3,016)	124
Adjustment to funded status of employee benefit plans, Pre-Tax Amount	18,299	(271)	(18,787)
Other Comprehensive (Loss) Income, Pre-Tax Amount	1,366	810	(11,961)
Tax (Expense) Benefit
Net change in unrealized (losses) gains on securities available-for-sale, Tax (Expense) Benefit	5,925	(1,434)	(2,346)
Net available-for-sale securities (gains) losses reclassified into earnings, Tax (Expense) Benefit	2	1,055	(43)
Adjustment to funded status of employee benefit plans, Tax (Expense) Benefit	(6,405)	95	6,576
Other Comprehensive (Loss) Income, Tax (Expense) Benefit	(478)	(284)	4,187
Net of Tax Amount
Net change in unrealized (losses) gains on securities available-for-sale, Net of Tax Amount	(11,003)	2,663	4,356
Net available-for-sale securities (gains) losses reclassified into earnings, Net of Tax Amount	(3)	(1,961)	81
Adjustment to funded status of employee benefit plans, Net of Tax Amount	11,894	(176)	(12,211)
Other Comprehensive Income (Loss), After Tax	$ 888	$ 526	$ (7,774)