Employee Benefit Plans (Schedule of Net Benefit Costs) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 27,065	$ 27,466	$ 16,490
Interest cost	16,207	15,668	16,253
Curtailments	47	324	0
Expected return on plan assets	(23,761)	(22,030)	(21,812)
Amortization of prior service cost (credit)	(204)	259	(189)
Amortization of other actuarial (gains) losses	14,616	14,666	8,748
Total net benefit	33,970	36,353	19,490
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	2,027	2,142	3,917
Interest cost	1,739	2,020	3,279
Curtailments	(5,444)	(4,049)	0
Expected return on plan assets	0	0	0
Amortization of prior service cost (credit)	(10,621)	(11,458)	(2,364)
Amortization of other actuarial (gains) losses	(252)	(522)	(3,100)
Total net benefit	$ (12,551)	$ (11,867)	$ 1,732