Derivative Financial Instruments Activity of Hedging Instruments in Accumulated OCI (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Net unrealized gain (loss) on hedging instruments at January 1,	$ (14,380)	$ (10,034)
Unrealized gain (loss) on derivative instruments	(1,689)	1,909	(2,930)
Unrealized gain (loss) on a nonderivative net investment hedging instrument	0	(8,866)	15,825
Realized (gains) losses reclassified into net income (loss)	0	2,611	7,371
Net unrealized gain (loss) on hedging instruments at December 31,	(16,069)	(14,380)	(10,034)
Net Investment Hedging [Member]
Net unrealized gain (loss) on hedging instruments at December 31,	$ 14,400