Accumulated Other Comprehensive Income (Loss) (Reclassifications Out of Accumulated Other Comprehensive Income (Loss)) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013
Amortization of defined benefit pension and supplemental benefit plan items:
Amortization of net actuarial loss					$ 14,814
Amortization of prior service credit					(2,076)
Net Unrealized Gains (Losses) on Securities
Net unrealized gains (losses) on securities:
Pretax total	6,840		4,691		9,009		11,254
Pension Benefit Adjustment
Amortization of defined benefit pension and supplemental benefit plan items:
Amortization of net actuarial loss					14,814
Amortization of prior service credit					(2,076)
Pension benefit adjustment, Reclassifications out of AOCI	6,369		6,906		12,738		13,812
Amounts Reclassified from Accumulated Other Comprehensive Income | Net Unrealized Gains (Losses) on Securities
Net unrealized gains (losses) on securities:
Net realized gains on sales of securities	7,355		4,691		10,042		11,254
Net OTTI losses recognized in earnings	(515)				(1,033)
Pretax total	6,840		4,691		9,009		11,254
Tax effect	(2,661)		(1,876)		(3,505)		(4,502)
Amounts Reclassified from Accumulated Other Comprehensive Income | Pension Benefit Adjustment
Amortization of defined benefit pension and supplemental benefit plan items:
Amortization of net actuarial loss	(7,407)	[1]	(8,002)	[1]	(14,814)	[1]	(16,004)	[1]
Amortization of prior service credit	1,038	[1]	1,096	[1]	2,076	[1]	2,192	[1]
Pension benefit adjustment, Reclassifications out of AOCI	(6,369)		(6,906)		(12,738)		(13,812)
Tax effect	$ 2,477		$ 2,763		$ 4,955		$ 5,525

[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.