Pension And Other Postretirement Benefit Plans (Components Of Net Periodic Cost) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended			6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Mar. 31, 2012	Jun. 30, 2013	Jun. 30, 2012
Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1,498	$ 3,495		$ 3,027	$ 6,990
Interest cost	8,878	9,334		18,289	18,668
Expected return on plan assets	(12,728)	(12,830)		(25,941)	(25,660)
Amortization of prior service cost	13	100		7	200
Amortization of net loss (gain)	3,723	4,816		6,887	9,623
Defined Benefit Plan, Settlements, Benefit Obligation	1,384		4,915	2,269	9,821
Other Postretirement Benefit Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Service cost	18	29		45	58
Interest cost	62	127		186	254
Amortization of prior service cost	(59)	(59)		(118)	(118)
Amortization of net loss (gain)	12	(21)		(23)	(42)
Net periodic cost	$ 33	$ 76		$ 90	$ 152