Accumulated Other Comprehensive Income (Loss) (Reclassifications Out of Accumulated Other Comprehensive Income) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013
Net unrealized gains (losses) on securities:
Net realized gains on sales of securities	$ 2,884		$ 6,012
Net OTTI losses recognized in earnings	(518)
Pretax total	2,366		6,012
Tax effect	(921)		(2,407)
Amortization of defined benefit pension and supplemental benefit plan items:
Net actuarial loss	(7,407)	[1]	(8,002)	[1]
Accumulated other comprehensive income (loss), Amortization of prior service credit	1,038	[1]	1,096	[1]
Pretax total	(6,369)		(6,906)
Tax effect	$ 2,478		$ 2,762

[1] These accumulated other comprehensive income components are included in the computation of net periodic cost. See Note 11 Employee Benefit Plans for additional details.