Derivative Financial Instruments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Losses and (gains) on derivative financial instruments
Loss (gain) on derivatives	$ 65	$ (536)	$ (14)	$ 487
Interest rate swaps [Member]
Losses and (gains) on derivative financial instruments
Loss (gain) on derivatives		6	26	146
Currency swap [Member]
Losses and (gains) on derivative financial instruments
Loss (gain) on derivatives	$ 65	$ (542)	$ (40)	$ 341