Disclosures About Offsetting Assets And Liabilities (Financial Assets And Derivative Assets That Are Subject To Offset) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Disclosures About Offsetting Assets And Liabilities [Abstract]
Gross amounts of recognized assets, Securities borrowing	$ 445,542	[1]	$ 227,640	[1]
Gross amounts offset in the Statement of Financial Condition, Securities borrowing		[1]		[1]
Net amounts presented in the Statement of Financial Condition	445,542	[1]	227,640	[1]
Gross amounts not offset in the Statement of Financial Position, Financial instruments, Securities borrowing		[1]		[1]
Gross amounts not offset in the Statement of Financial Position, Collateral received, Securities borrowing	(431,301)	[1]	(219,992)	[1]
Securities borrowed, Net amount	14,241	[1]	7,648	[1]
Gross amounts of recognized assets, Reverse repurchase agreements	55,078	[2]	225,075	[2]
Gross amounts offset in the statement of Financial Condition, Securities purchased under agreements to resell		[2]		[2]
Net amounts presented in the Statement of Financial Condition, Securities purchased under agreements to resell	55,078	[2]	225,075	[2]
Gross amounts not offset in the Statement of Financial Position, Financial instruments, Securities purchased under agreements to resell		[2]		[2]
Gross amounts not offset in the Statement of Financial Position, Collateral received, Securities purchased under agreements to resell	(54,955)	[2]	(224,566)	[2]
Securities purchased under agreements to resell, Net amount	123	[2]	509	[2]
Gross amounts of recognized assets, Cash flow interest rate contracts
Gross amounts offset in the Statement of Financial Condition, Cash flow interest rate contracts
Net amounts presented in the Statement of Financial Condition
Gross amounts not offset in the Statement of Financial Position, Financial instruments, Cash flow interest rate contracts
Gross amounts not offset in the Statement of Financial Position, Financial instruments, Cash flow interest rate contracts
Cash flow interest rate contracts, Net amount
Gross amounts of recognized assets	500,620		452,715
Gross amounts offset in the Statement of Financial Condition
Net amounts presented in the Statements of Financial Condition	500,620		452,715
Gross amounts not offset in the Statement of Financial Position
Gross amounts not offset in the Statement of Financial Position, Collateral received	(486,256)		(444,558)
Net amount	$ 14,364		$ 8,157

[1] Securities borrowing transactions are included in receivables from brokers, dealers, and clearing organizations on the consolidated statements of financial condition. See Note 5 in the notes to consolidated financial statements for additional information on receivables from brokers, dealers, and clearing organizations.(2)

[2] Collateral received includes securities received by our company from the counterparty. These securities are not included on the consolidated statements of financial condition unless there is an event of default.