Federal Home Loan Bank Advances, Other Borrowings and Subordinated Notes Federal Home Loan Bank Advances, Other Borrowings and Subordinated Notes (Summary of Debt) (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014
Debt Disclosure [Abstract]
Federal Home Loan Bank advances	$ 451,330	$ 733,050	$ 347,500
Other borrowings:
Notes payable	71,250	0	0
Securities sold under repurchase agreements	57,590	48,566	32,530
Other	18,466	18,822	18,953
Secured borrowings	112,672	129,077	0
Total other borrowings	259,978	196,465	51,483
Subordinated notes	140,000	140,000	140,000
Total Federal Home Loan Bank advances, other borrowings and subordinated notes	$ 851,308	$ 1,069,515	$ 538,983