Derivative Financial Instruments - Gross Gains (Losses) Reclassified from Accumulated Other Comprehensive Income (Details) (Interest Rate Swap, USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Designated as Cash Flow Hedges
Derivative Instruments Gain Loss [Line Items]
Gross Gains (Losses) Recognized in Interest Expense	$ (47)	$ 0	$ 91	$ 0
Gross Gains (Losses) Recognized in Accumulated Other Comprehensive Income	(7,246)	(1,155)	(6,592)	(1,660)
Gross Gains (Losses) Reclassified From Accumulated Other Comprehensive Income to Interest Expense	(1,931)	(4,444)	(4,595)	(9,439)
Not Designated As Hedges
Derivative Instruments Gain Loss [Line Items]
Gross Gains (Losses) Recognized in Interest Expense	$ 3,199	$ 10,682	$ 8,388	$ 17,339