Pension and Postretirement Plans (Total Benefit/Cost) (Details 5) (USD $) In Thousands, unless otherwise specified	3 Months Ended					12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Net Periodic Cost (Benefit)	$ (16,600)				$ 4,390
Early retirement program expense	4,490				14,258
Total Cost (Benefit)	(12,188)	(9,058)	(2,687)	(2,601)	(2,673)	(17,019)	(8,532)
Amortization of prior service credit (cost)	(102)				(437)
Curtailment loss	0				(3,471)
Total Recognized in Other Comprehensive Income (Before Tax Effects)	7,284				1,591
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	7,537				13,365
Interest cost	13,082				14,291
Expected return on assets	(30,263)				(26,322)
Amortization of prior service cost (credit)	82				909
Recognized actuarial loss (gain)	(7,038)				2,147
Net Periodic Cost (Benefit)	(16,600)				4,390
Early retirement program expense	4,490				14,258
Total Cost (Benefit)	(12,110)				18,648
Supplemental Executive Retirement Plan (SERP) [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	373				429
Interest cost	1,085				1,023
Amortization of prior service cost (credit)	12				14
Recognized actuarial loss (gain)	375				711
Total Cost (Benefit)	1,845				2,177
Other Postretirement Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	375				727
Interest cost	362				510
Amortization of prior service cost (credit)	(196)				(1,360)
Recognized actuarial loss (gain)	(519)				(541)
Net Periodic Cost (Benefit)	22				(664)
Settlement gain	0				(3,471)
Total Cost (Benefit)	$ 22				$ (4,135)