Derivatives and Hedging Instruments (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Interest rate swaps [Member]
Summary of the effects of derivatives in cash flow hedging relationships on statements of income
Gain or (Loss) Recognized in OCI- Effective Portion	$ 62	$ (795)	$ (9)	$ (1,361)
Foreign currency exchange contracts 1 [Member]
Summary of the effects of derivatives in cash flow hedging relationships on statements of income
Gain or (Loss) Recognized in OCI- Effective Portion	2,131	(984)	(69)	(387)
Foreign currency exchange contracts 2 [Member]
Summary of the effects of derivatives in cash flow hedging relationships on statements of income
Gain or (Loss) Recognized in OCI- Effective Portion	377	(230)	173	(108)
Interest Expense [Member] | Interest rate swaps [Member]
Summary of the effects of derivatives in cash flow hedging relationships on statements of income
Gain or (Loss) Reclassified from OCI into Income - Effective Portion
Salaries and employee benefits [Member] | Foreign currency exchange contracts 1 [Member]
Summary of the effects of derivatives in cash flow hedging relationships on statements of income
Gain or (Loss) Reclassified from OCI into Income - Effective Portion	(389)	27	(946)	194
General and administrative expenses [Member] | Foreign currency exchange contracts 2 [Member]
Summary of the effects of derivatives in cash flow hedging relationships on statements of income
Gain or (Loss) Reclassified from OCI into Income - Effective Portion	(69)	6	(164)	44
Other (expense) income [Member] | Interest rate swaps [Member]
Summary of the effects of derivatives in cash flow hedging relationships on statements of income
Amount of Gain or (Loss) Recognized - Ineffective Portion and Amount Excluded from Effectiveness Testing
Other (expense) income [Member] | Foreign currency exchange contracts 1 [Member]
Summary of the effects of derivatives in cash flow hedging relationships on statements of income
Amount of Gain or (Loss) Recognized - Ineffective Portion and Amount Excluded from Effectiveness Testing
Other (expense) income [Member] | Foreign currency exchange contracts 2 [Member]
Summary of the effects of derivatives in cash flow hedging relationships on statements of income
Amount of Gain or (Loss) Recognized - Ineffective Portion and Amount Excluded from Effectiveness Testing