Employee Benefit Plans (Schedule of Defined Benefit Plans Disclosures) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Value of Plan Assets at December 31		$ 347,952
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit Obligations at January 1	355,468	390,894
Service cost	21,478	27,065	27,466
Interest cost	17,070	16,207	15,668
Plan Amendments	(23)	0
Benefits Paid	(53,974)	(41,562)
Curtailments	(25,787)	(3,027)
Other-primary actuarial loss (gain)	39,504	(34,109)
Benefit Obligations at December 31	353,736	355,468	390,894
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Value of Plan Assets at January 1	347,952	322,874
Actual Return on Plan Assets	36,130	52,247
Employer contributions	6,601	14,393
Benefits Paid	(53,974)	(41,562)
Value of Plan Assets at December 31	336,709	347,952	322,874
Accrued benefit cost	(17,027)	(7,516)
Prior service cost (credit)	0	1,732
Accumulated gain (loss)	(11,332)	10,096
Total not yet recognized as a component of net periodic benefit cost	(11,332)	11,828
Current liability	(767)	(405)
Noncurrent liability	(16,260)	(7,111)
Pension and Other Postretirement Defined Benefit Plans, Liabilities	(17,027)	(7,516)
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit Obligations at January 1	42,531	49,326
Service cost	1,649	2,027	2,142
Interest cost	1,841	1,739	2,020
Plan Amendments	0	0
Benefits Paid	(3,431)	(3,276)
Curtailments	0	(2,519)
Other-primary actuarial loss (gain)	(6,492)	(4,766)
Benefit Obligations at December 31	36,098	42,531	49,326
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Value of Plan Assets at January 1	0	0
Actual Return on Plan Assets	0	0
Employer contributions	3,431	3,276
Benefits Paid	(3,431)	(3,276)
Value of Plan Assets at December 31	0	0	0
Accrued benefit cost	(36,098)	(42,531)
Prior service cost (credit)	21,972	31,925
Accumulated gain (loss)	9,125	3,394
Total not yet recognized as a component of net periodic benefit cost	31,097	35,319
Current liability	(3,430)	(3,276)
Noncurrent liability	(32,668)	(39,255)
Pension and Other Postretirement Defined Benefit Plans, Liabilities	$ (36,098)	$ (42,531)