Employee Benefit Plans Benefit Obligation And Funded Status (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Pension Plan, Defined Benefit [Member]
Change in Benefit Obligation:
Obligation beginning of period	$ 609,643,000	$ 536,536,000
Service cost	13,465,000	11,488,000
Interest cost	22,719,000	23,823,000
Actuarial (gain) loss	(54,671,000)	59,071,000
Benefits paid	(23,290,000)	(21,275,000)
Benefit obligation end of period	567,866,000	609,643,000
Change in Fair Value of Plan Assets:
Benefits paid	(23,290,000)	(21,275,000)
Amounts recognized in balance sheet consist of:
Current liability	0	0
Noncurrent liability	(51,514,000)	(136,707,000)
Net amount recognized	(51,514,000)	(136,707,000)
Amounts recognized in AOCI consist of:
Prior service cost	0	0
Net actuarial gain	0	0
Total	(72,525,000)	(161,604,000)
Plans with Benefit Obligations in Excess of Plan Assets [Abstract]
Projected benefit obligation	567,900,000	609,600,000
Accumulated benefit obligation	565,000,000	606,200,000
Fair value of plan assets	516,400,000	472,900,000
Pension Plan, Defined Benefit [Member] | Pension Costs [Member]
Amounts recognized in regulatory assets consist of:
Prior service (cost) credit	(748,000)	(994,000)
Net actuarial loss	(71,777,000)	(160,610,000)
Pension Plan, Defined Benefit [Member] | Changes Measurement [Member]
Change in Benefit Obligation:
Benefits paid	(23,290,000)	(21,275,000)
Change in Fair Value of Plan Assets:
Fair value of plan assets at beginning of period	472,936,000	432,637,000
Return on plan assets	55,006,000	49,874,000
Employer contributions	11,700,000	11,700,000
Benefits paid	(23,290,000)	(21,275,000)
Fair value of plan assets at end of period	516,352,000	472,936,000
Funded Status	(51,514,000)	(136,707,000)
Other Postretirement Benefit Plan, Defined Benefit [Member]
Change in Benefit Obligation:
Obligation beginning of period	34,040,000	32,427,000
Service cost	541,000	541,000
Interest cost	877,000	1,167,000
Actuarial (gain) loss	(3,156,000)	2,508,000
Benefits paid	(2,218,000)	(2,603,000)
Benefit obligation end of period	30,084,000	34,040,000
Change in Fair Value of Plan Assets:
Benefits paid	(2,218,000)	(2,603,000)
Amounts recognized in balance sheet consist of:
Current liability	(1,178,000)	(1,082,000)
Noncurrent liability	(10,723,000)	(17,065,000)
Net amount recognized	(11,901,000)	(18,147,000)
Amounts recognized in AOCI consist of:
Prior service cost	(1,302,000)	(1,453,000)
Net actuarial gain	(971,000)	(2,432,000)
Total	12,167,000	8,023,000
Other Postretirement Benefit Plan, Defined Benefit [Member] | Pension Costs [Member]
Amounts recognized in regulatory assets consist of:
Prior service (cost) credit	19,247,000	21,396,000
Net actuarial loss	(4,807,000)	(9,488,000)
Other Postretirement Benefit Plan, Defined Benefit [Member] | Changes Measurement [Member]
Change in Benefit Obligation:
Benefits paid	(2,218,000)	(2,603,000)
Change in Fair Value of Plan Assets:
Fair value of plan assets at beginning of period	15,893,000	15,502,000
Return on plan assets	2,662,000	1,789,000
Employer contributions	1,846,000	1,205,000
Benefits paid	(2,218,000)	(2,603,000)
Fair value of plan assets at end of period	18,183,000	15,893,000
Funded Status	$ (11,901,000)	$ (18,147,000)