Derivatives (Narrative - Interest Rate Swaps) (Details) (Interest Rate Contracts, Fair Value Hedging, USD $)	3 Months Ended		12 Months Ended						3 Months Ended	1 Months Ended
	Jun. 30, 2012 Old Rate Agreement	Jun. 30, 2012 Interest Expense Old Rate Agreement	Dec. 31, 2012 Designated as Hedging Instrument	Dec. 31, 2011 Designated as Hedging Instrument	Dec. 31, 2010 Designated as Hedging Instrument	Dec. 31, 2012 Designated as Hedging Instrument Loss on Redemption of Debt	Dec. 31, 2011 Designated as Hedging Instrument Loss on Redemption of Debt	Dec. 31, 2010 Designated as Hedging Instrument Loss on Redemption of Debt	Jun. 30, 2012 Designated as Hedging Instrument Loss on Redemption of Debt Old Rate Agreement	Aug. 31, 2011 Old Senior Secured Notes Senior Notes Old Rate Agreement	Aug. 31, 2010 Old Senior Secured Notes Senior Notes Old Rate Agreement	Apr. 17, 2012 Old Senior Secured Notes Senior Notes Old Rate Agreement	Dec. 31, 2010 Old Senior Secured Notes Senior Notes Old Rate Agreement	Dec. 31, 2012 New Senior Secured Notes Senior Notes New Rate Agreement [Member]
Derivative [Line Items]
Derivative, notional amount												$ 80,000,000	$ 100,000,000	$ 45,000,000
Derivative, notional amount terminated										10,000,000	10,000,000
Termination premium										300,000	300,000
Proceeds from termination of hedge	3,600,000
Related long-term debt		100,000	3,635,000	(777,000)	(3,266,000)				3,502,000
Loss on redemption of debt						$ 3,502,000	$ 0	$ 0