Income Taxes (Narrative) (Details) (USD $)	3 Months Ended		6 Months Ended		36 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Dec. 31, 2012
Income Tax Contingency [Line Items]
Net deferred tax asset	$ 789,525,000		$ 789,525,000		$ 789,525,000	$ 806,406,000
Valuation allowance	20,100,000		20,100,000		20,100,000	18,700,000
Cumulative loss position	72,906,000	37,347,000	119,459,000	73,262,000	249,000,000
Amount expected to be realized	789,500,000		789,500,000		789,500,000
Deferred tax assets, not subject to expiration	209,300,000		209,300,000		209,300,000
Unrecognized tax benefits	1,200,000		1,200,000		1,200,000	1,100,000
Period from Twenty Twety Eight Throught Twenty Thirty Two [Member]
Income Tax Contingency [Line Items]
Operating loss carryforwards, subject to expiration	485,500,000		485,500,000		485,500,000
Period from Twenty Thirteen Through Twenty Thirty Two [Member]
Income Tax Contingency [Line Items]
Operating loss carryforwards, subject to expiration	27,500,000		27,500,000		27,500,000
State and Local Jurisdiction [Member] | Period from Twenty Eighteen Through Twenty Thirty Two [Member]
Income Tax Contingency [Line Items]
Operating loss carryforwards, subject to expiration	67,000,000		67,000,000		67,000,000
Domestic Tax Authority [Member]
Income Tax Contingency [Line Items]
Tax credit carryforwards, alternative minimum tax	$ 20,300,000		$ 20,300,000		$ 20,300,000