Commitments and Contingent Liabilities (Details) (USD $)	Mar. 31, 2012	Dec. 31, 2011
Commitments and Contingent Liabilities (Textual) [Abstract]
Loan commitments outstanding	$ 1,658,992	$ 1,667,859
Commercial Letters of Credit [Member]
Commitments and Contingent Liabilities (Textual) [Abstract]
Letters of credit issued	293,000	290,000
Standby Letters of Credit [Member]
Commitments and Contingent Liabilities (Textual) [Abstract]
Letters of credit issued	$ 115,518,000	$ 130,034,000