Pension and Postretirement Plans (Accumulated Other Comprehensive Income) (Details 7) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plan Disclosure [Line Items]
Net amount	$ 117,169	$ 63,625
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Unrecognized actuarial (gain) loss	(193,469)	(105,051)
Unrecognized prior service cost	15,931	19,626
Gross amount	(177,538)	(85,425)
Deferred tax liability (asset)	71,015	34,170
Net amount	(106,523)	(51,255)
Supplemental Executive Retirement Plan (SERP) [Member]
Defined Benefit Plan Disclosure [Line Items]
Unrecognized actuarial (gain) loss	33,725	26,385
Unrecognized prior service cost	191	245
Gross amount	33,916	26,630
Deferred tax liability (asset)	(13,566)	(10,652)
Net amount	20,350	15,978
Other Postretirement Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Unrecognized actuarial (gain) loss	(25,525)	(15,510)
Unrecognized prior service cost	(26,128)	(31,736)
Gross amount	(51,653)	(47,246)
Deferred tax liability (asset)	20,661	18,898
Net amount	$ (30,992)	$ (28,348)