Derivative Instruments (Details 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Credit-risk-related Contingent Features
Accrued interest on termination value of derivatives in a liability position	$ 142		$ 142
Termination value of derivative in liability position	3,671		3,671
Termination value of derivative agreement	3,671		3,671
Interest rate swaps | Cash flow hedges
Derivative Financial Instruments
Amount of loss recognized in OCI on derivative (effective portion)	1,430	419	1,629	1,289
Amount of loss reclassified from accumulated OCI into income (effective portion)	449	279	1,038	2,260
Amount of loss recognized in income on derivative (ineffective portion and amount excluded from effectiveness testing and missed forecasted transactions)	$ 157	$ 148	$ 467	$ 157