Accumulated Other Comprehensive Loss (Amounts Reclassified from AOCI) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Interest Expense	$ 18,924	$ 18,431	$ 37,970	$ 37,394
Loss from Retirement of Debt	(623)	(4,436)	(623)	(5,586)
Total	(19,679)	(23,044)	(38,827)	(43,452)
Reclassification out of Accumulated Other Comprehensive Income | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total	1,547	1,514	2,908	2,282
Interest Rate Contract | Reclassification out of Accumulated Other Comprehensive Income | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Interest Expense	468	598	1,096	1,183
Loss from Retirement of Debt	0	916	0	1,099
Interest Rate Swap | Reclassification out of Accumulated Other Comprehensive Income | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Interest Expense	$ 1,079	$ 0	$ 1,812	$ 0