Financial Guarantees (Details Textual) (USD $)	6 Months Ended
	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2011
Financial Guarantees (Textual) [Abstract]
Expiry of letters of credit, maximum	5 years
Other Liabilities	$ 41,323,000	$ 54,024,000	$ 33,919,000
Financial Standby Letter of Credit [Member]
Financial Guarantees (Textual) [Abstract]
Letters of credit outstanding	44,000,000	46,000,000	48,000,000
Other Liabilities	$ 0	$ 300,000	$ 300,000