Equity and Capital Equity and Capital - Common Stock (Details) (USD $) Share data in Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Aug. 10, 2013 Maximum [Member]	Mar. 31, 2014 Accumulated Other Comprehensive Income (Loss) [Member]	Dec. 31, 2013 Accumulated Other Comprehensive Income (Loss) [Member]	Mar. 31, 2013 Accumulated Other Comprehensive Income (Loss) [Member]	Dec. 31, 2012 Accumulated Other Comprehensive Income (Loss) [Member]	Mar. 31, 2014 Loss on Settlement of Derivative Instruments [Member]	Dec. 31, 2013 Loss on Settlement of Derivative Instruments [Member]	Mar. 31, 2013 Loss on Settlement of Derivative Instruments [Member]	Dec. 31, 2012 Loss on Settlement of Derivative Instruments [Member]	Mar. 31, 2014 Fair Value of Derivative Instruments [Member]	Dec. 31, 2013 Fair Value of Derivative Instruments [Member]	Mar. 31, 2013 Fair Value of Derivative Instruments [Member]	Dec. 31, 2012 Fair Value of Derivative Instruments [Member]
Class of Stock [Line Items]
Amount reclassified from accumulated other comprehensive loss	$ (2,474,000)	$ (2,366,000)
Shares issued	0	996
Accumulated other comprehensive loss				(28,599,000)	(17,404,000)	(51,983,000)	(57,715,000)	(50,180,000)	(52,542,000)	(59,629,000)	(61,991,000)	21,581,000	35,138,000	7,646,000	4,276,000
Equity Issuances, Amount Available for Issuance	200,000,000		200,000,000
Weighted Average Price Per Share		$ 52.62
Net proceeds from common stock issuance		52,398,000
Payments for Commissions		787,000
Payments of Stock Issuance Costs		$ 3,000