Employee Benefits Plans (Narrative) (Details) (USD $)	6 Months Ended	12 Months Ended
	Jun. 30, 2009	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Jun. 25, 2009
Defined Benefit Plan Disclosure [Line Items]
Prepaid pension asset		$ 35,100,000	$ 41,000,000
Accumulated benefit obligation of the Pension Plan		25,800,000	28,800,000
Estimated actuarial loss and prior service cost that will be amortized from accumulated from accumulated other comprehensive income into net periodic pension cost (credit)		0	400,000	0
Settlement losses and curtailment charges		5,900,000	4,100,000
Purchase price of the group annuity contract					101,000,000
Transfer and settlement of pension benefit obligations					93,000,000
Non-cash pre-tax settlement charge to earnings	44,700,000
Pre-tax credit in Accumulated Other Comprehensive Income	44,700,000	(9,880,000)	(10,546,000)
Expected long-term rate of return on plan assets		5.00%	6.00%	8.00%
Matching contributions for the first 1%		100.00%
Matching contributions equal to 100%		1.00%
Matching contributions for the next 5%		50.00%
Matching contributions equal to 50%		5.00%
Maximum eligible compensation		3.50%
Company contributions to the plan		200,000	400,000	600,000
Defined benefit plan, benefits paid		(16,000)	(11,000)
Retiree medical liability		10,500,000
Reduction in accumulated other comprehensive income (loss)		5,000,000
Employee insurance expense		5,500,000
Accrued liabilities		1,687,000	7,059,000
Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Fixed income investment, overall investment strategy		95.00%
Overall investment strategy, equity type investment		35.00%
Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Fixed income investment, overall investment strategy		65.00%
Overall investment strategy, equity type investment		5.00%
Large Cap Equities [Member]
Defined Benefit Plan Disclosure [Line Items]
Common/collective trusts invest percentage		25.00%
International Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Common/collective trusts invest percentage, international		8.00%
Fund Postretirement Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Common collective trusts investment percentage, fixed income investments		67.00%
Accrued liabilities		$ 100,000	$ 11,300,000