Accumulated Other Comprehensive Income (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended			3 Months Ended		9 Months Ended			3 Months Ended		9 Months Ended		3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013 Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]	Sep. 30, 2013 Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] Interest Rate Contract		Sep. 30, 2013 Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] Interest Rate Contract		Mar. 31, 2013 Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] Interest Rate Contract	Sep. 30, 2013 Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] Interest Rate Contract Reclassification out of Accumulated Other Comprehensive Income [Member]		Sep. 30, 2013 Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] Interest Rate Contract Reclassification out of Accumulated Other Comprehensive Income [Member]		Sep. 30, 2013 Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges Amortization [Member] Interest Rate Contract Reclassification out of Accumulated Other Comprehensive Income [Member]	Sep. 30, 2013 Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges Amortization [Member] Interest Rate Contract Reclassification out of Accumulated Other Comprehensive Income [Member]	Sep. 30, 2013 Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges, Net Settlements [Member] Interest Rate Contract Reclassification out of Accumulated Other Comprehensive Income [Member]	Sep. 30, 2013 Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges, Net Settlements [Member] Interest Rate Contract Reclassification out of Accumulated Other Comprehensive Income [Member]
Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance			$ (126,290)					$ (126,290)		$ (96,352)
Amount recognized in other comprehensive loss on derivatives, net of tax benefit of $43 and tax expense of $21, respectively						(2,556)	[1]	403	[1]
Amount of loss reclassified from accumulated other comprehensive loss into income(c)						11,654	[2]	38,633	[2]		11,654	[2]	38,633	[2]
Net current period other comprehensive income	9,098	10,392	39,036	45,611		9,098		39,036
Ending balance	(87,254)		(87,254)			(87,254)		(87,254)		(96,352)
Tax Expense from Amount Recognized in Other Comprehensive Income Related to Derivatives	78	37	389	465	21	43
Tax Expense from Amount Reclassified from Accumulated Other Comprehensive Income into Income																	121	368
Interest Expense	$ 58,051	$ 54,204	$ 184,335	$ 168,965											$ 7,300	$ 25,285	$ 4,354	$ 13,348

[1] This represents the change in fair market value of our interest rate derivatives since year end, net of taxes, offset by the amount of actual cash paid related to the net settlements of the interest rate derivatives for the nine months ended September 30, 2013.

[2] This represents the amount of actual cash paid, net of taxes, related to the net settlements of the interest rate derivatives for the nine months ended September 30, 2013 plus any effective amortization of net deferred interest rate derivative losses.