Pension Plan Obligations and Funded Status (Details) (USD $)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	$ 38,947,000		$ (38,234,000)		$ 8,440,000
Decrease of deferred tax assets	25,888,000		30,128,000
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at beginning of year	555,400,000
Fair value of plan assetss at end of year	596,733,000		555,400,000
Current liabilities (a)	(300,000)
Noncurrent liabilities	(141,546,000)		(85,835,000)
Supplemental Employee Retirement Plan [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Projected benefit obligation at beginning of year	9,910,000		12,326,000
Service cost	256,000		340,000		380,000
Interest cost	342,000		311,000		408,000
Actuarial liability (gain) loass (a)	660,000	[1]	(458,000)	[1]
Benefit payments	(819,000)		(2,291,000)
(Curtailment) / Settlement	0		(318,000)
Projected benefit obligation at end of year	10,349,000		9,910,000		12,326,000
Fair value of plan assets at beginning of year	0		0
Actual return on plan assets	0		0
Employer contributions	819,000		2,291,000
Fair value of plan assetss at end of year	0		0		0
Funded status at end of year	(10,349,000)		(9,910,000)
Accumulated benefit obligation	10,349,000		9,910,000
Current liabilities (a)	(531,000)		(819,000)
Noncurrent liabilities	(9,818,000)		(9,091,000)
Total	(10,349,000)		(9,910,000)
Unrecognized (gain) or loss	1,609,000		1,040,000
Unrecognized prior service cost (credit)	0		0
Amount included in accumulated other comprehensive income (loss)	1,609,000		1,040,000
Qualified pension plan and SERP that will be amortized from accumulated other comprehensive income (loss) in next fiscal year	200,000
Qualified Pension Plan [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Projected benefit obligation at beginning of year	641,235,000		706,356,000
Service cost	11,759,000		14,347,000		14,075,000
Interest cost	28,835,000		25,596,000		26,312,000
Actuarial liability (gain) loass (a)	84,848,000	[1]	(78,609,000)	[1]
Benefit payments	(28,398,000)		(26,455,000)
(Curtailment) / Settlement	0		0
Projected benefit obligation at end of year	738,279,000		641,235,000		706,356,000
Fair value of plan assets at beginning of year	555,400,000		557,653,000
Actual return on plan assets	59,731,000		14,202,000
Employer contributions	10,000,000		10,000,000
Fair value of plan assetss at end of year	596,733,000		555,400,000		557,653,000
Funded status at end of year	(141,546,000)		(85,835,000)
Accumulated benefit obligation	738,279,000		641,235,000
Current liabilities (a)	0	[2]	0
Noncurrent liabilities	(141,546,000)		(85,835,000)
Total	(141,546,000)		(85,835,000)
Unrecognized (gain) or loss	167,329,000		105,269,000
Unrecognized prior service cost (credit)	57,000		156,000
Amount included in accumulated other comprehensive income (loss)	167,386,000		105,425,000
Qualified pension plan and SERP that will be amortized from accumulated other comprehensive income (loss) in next fiscal year	$ 9,600,000

[1] (a) The actuarial liability (gain)/loss amount for the qualified pension plan for 2014 and 2013 is principally due to the effect of changes in the discount rate. Additionally, in 2014 a new set of mortality tables was issued by the Society of Actuaries ("SOA"), which impacted the valuation of the Company's obligations under the qualified pension plan and SERP.

[2] (a) The current liabilities are included in other accruals and payables on the Consolidated Balance Sheets