Derivative Financial Instruments Activity of Hedging Instruments in Accumulated OCI (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Net unrealized loss on hedging instruments at beginning			$ (14,380)	$ (10,034)
Unrealized gain (loss) on derivative instruments	(849)	(224)	(849)	(164)
Net unrealized gain (loss) on nonderivative hedging instruments	0	(1,452)	0	(9,262)
Realized (gains) losses reclassified into net income (loss)	0	1,332	0	2,774
Net unrealized loss on hedging instruments at end	(15,229)	(16,686)	(15,229)	(16,686)
Net Investment Hedging [Member]
Net unrealized loss on hedging instruments at end	$ (14,400)		$ (14,400)