Derivatives and Hedging Instruments (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Interest rate swaps [Member] | Other liabilities [Member]
Summary of fair value of derivative instruments as recorded in consolidated statements of financial position
Derivatives designated as hedging instruments	$ (1,023)	$ (1,014)
Foreign currency exchange contracts [Member] | Other liabilities [Member]
Summary of fair value of derivative instruments as recorded in consolidated statements of financial position
Derivatives designated as hedging instruments	(1,035)	(2,371)
Foreign currency exchange contracts [Member] | Other assets [Member]
Summary of fair value of derivative instruments as recorded in consolidated statements of financial position
Derivatives designated as hedging instruments	$ 46	$ 168