Notes Payable, Federal Home Loan Bank Advances, Other Borrowings, Secured Borrowings And Subordinated Notes (Summary Of Notes Payable, Federal Home Loan Bank Advances, Other Borrowings, Secured Borrowings And Subordinated Notes) (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Jun. 30, 2012	Dec. 31, 2011	Sep. 30, 2011
Disclosure Notes Payable FHLB Advances Other Borrowings Secured Borrowings And Subordinated Notes Summary Of Notes Payable FHLB Advances Other Borrowings Secured Borrowings And Sub Notes [Abstract]
Notes payable	$ 2,275		$ 52,822	$ 3,004
Federal Home Loan Bank advances	414,211		474,481	474,570
Securities sold under repurchase agreements	337,405		413,333	414,333
Other	39,824		30,420	33,749
Total other borrowings	377,229		443,753	448,082
Secured borrowings-owed to securitization investors	0	360,800	600,000	600,000
Subordinated notes	15,000		35,000	40,000
Total notes payable, Federal Home Loan Bank advances, other borrowings, secured borrowings, and subordinated notes	$ 808,715		$ 1,606,056	$ 1,565,656