Derivatives (Details 1) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Interest Expense From Accumulated OCI [Member]
Effect of derivative financial instruments in statement of operations and other comprehensive income
Amount of Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	$ 1,225	$ (2,129)
Interest Expense [Member]
Effect of derivative financial instruments in statement of operations and other comprehensive income
Amount of Gain or (Loss) Recognized in Income on Derivative (Ineffective Portion and Amount Excluded from Effectiveness Testing)	0	(71)
Interest Rate Products [Member]
Effect of derivative financial instruments in statement of operations and other comprehensive income
Amount of Gain or (Loss) Recognized in OCI on Derivative (Effective Portion)	$ 549	$ (170)