Commitments and Contingencies (Details) (USD $)	Jun. 30, 2011	Dec. 31, 2010
Commitments and Contingencies (Textuals) [Abstract]
Stand-by letters of credit, expiring at various dates	$ 86,900,000	$ 143,400,000
Amount outstanding under stand by letter of credit included in other liabilities	2,000,000	3,800,000
Unfunded commitments to extended credit to clients	1,400,000,000	1,900,000,000
Unfunded commitments to extended credit by subsidiary	810,000,000	958,700,000
Unfunded commitments to extended credit by Parent Company	$ 566,900,000	$ 977,700,000