| **Income Taxes (Narrative) (Details) - USD ($)**              | 1 Months Ended | 3 Months Ended | 12 Months Ended |
|---------------------------------------------------------------|----------------|----------------|-----------------|
||
| **Income Taxes [Line Items]**                                 |           |           |            |   |   |
| Statutory federal tax rate                                    |           |           | 21.00%          | 35.00% | 35.00% |
| Net income tax benefits                                       |           |           | $ 66,816,000    | $ 64,183,000 | $ 84,766,000 |
| Additional net income tax benefits                            |           | $ 3,141,000    |            |   |   |
| Effective income tax rate                                     |           |           | (6.20%)         | (7.70%) | 6.60% |
| Expected tax refund                                           |           |           | $ 3,907,000     |   |   |
| Unrecognized tax benefits                                     |           | 17,583,000     | 18,671,000      | $ 17,792,000 | $ 17,583,000 |
| Deferred income tax liabilities                               |           |           | 936,158,000     | 845,403,000 |   |
| Interest and penalties                                        |           | 0              | 0               | 0 | 0 |
| Federal [Member]                                              |           |           |            |   |   |
| **Income Taxes [Line Items]**                                 |           |           |            |   |   |
| Operating loss carryforwards                                  |           |           | 79,039,000      |   |   |
| Operating loss carryforwards, valuation allowance             |           |           | 0               |   |   |
| Operating loss carryforwards before unrecognized tax position |           |           | 152,391,000     |   |   |
| Unrecognized tax benefits                                     |           |           | 73,352,000      |   |   |
| State [Member]                                                |           |           |            |   |   |
| **Income Taxes [Line Items]**                                 |           |           |            |   |   |
| Deferred tax assets operating loss carryforward               |           |           | 817,323,000     |   |   |
| Operating loss carryforwards before unrecognized tax position |           |           | 902,968,000     |   |   |
| Unrecognized tax benefits                                     |           |           | 85,645,000      |   |   |
| Pennsylvania [Member]                                         |           |           |            |   |   |
| **Income Taxes [Line Items]**                                 |           |           |            |   |   |
| Net income tax benefits                                       |           |           | $ 31,015,000    | $ 26,990,000 |   |
| Decrease in current taxes payable                             | $ 16,724,000   |           |            |   |   |
| Reduction in state income tax expense                         | 158,865,000    |           |            |   |   |
| Target                                                        | 3,000,000      |           |            |   |   |
| Tax deduction                                                 | 380,000,000    |           |            |   |   |
| Amortization of benefit                                       | $ 38,000,000   |           |            |   |   |
| Term                                                          | 10 years       |           |            |   |   |
| Deferred income tax liabilities                               |           | $ 175,108,000  |            |   | $ 175,108,000 |
| Minimum [Member]                                              |           |           |            |   |   |
| **Income Taxes [Line Items]**                                 |           |           |            |   |   |
| State corporate net income tax rates                          |           |           | 2.50%           |   |   |
| Maximum [Member]                                              |           |           |            |   |   |
| **Income Taxes [Line Items]**                                 |           |           |            |   |   |
| State corporate net income tax rates                          |           |           | 9.99%           |   |   |
| Scenario, Plan [Member]                                       |           |           |            |   |   |
| **Income Taxes [Line Items]**                                 |           |           |            |   |   |
| Statutory federal tax rate                                    |           |           | 21.00%          |   |   |

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|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount before allocation of valuation allowances of deferred tax asset attributable to deductible domestic operating loss carryforwards. Excludes state and local operating loss carryforwards.
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| - Definition
Amount, after deferred tax asset, of deferred tax liability attributable to taxable differences without jurisdictional netting.
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| - Definition
Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.
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| - Definition
Percentage of domestic federal statutory tax rate applicable to pretax income (loss).
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| - Definition
Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to state and local income tax settlement.
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The amount of estimated penalties and interest accrued as of the balance sheet date arising from income tax examinations.
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| - Definition
Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to deductions. Including, but not limited to, extraterritorial income exclusion deduction, qualified production activity deduction, dividend deduction, deduction for dividend paid to employee stock ownership plan, Medicare prescription drug benefit subsidy deduction, and other deductions.
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| - Definition
Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws.
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| - Definition
The portion of the valuation allowance pertaining to the deferred tax asset representing potential future taxable deductions from net operating loss carryforwards for which it is more likely than not that a tax benefit will not be realized.
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Amount of other income tax expense (benefit).
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Amount of unrecognized tax benefits.
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Additional Other Tax Expense Benefit Recorded
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Amortization Of Income Tax Benefit
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Amortization Period, Tax Benefit
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Decrease In Current Taxes Payable
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Expected Tax Refund
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Income Taxes [Line Items]
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Operating loss carryforwards prior to being reduced by the unrecognized tax position
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State Income Tax Expense (Benefit) Increase
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Tax Benefit, Target
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