Federal Home Loan Bank Advances, Other Borrowings and Subordinated Notes (Summary of Debt) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015
Debt Disclosure [Abstract]
Federal Home Loan Bank advances	$ 799,482	$ 853,431	$ 406,839
Other borrowings:
Notes payable	63,683	67,429	0
Short-term borrowings	47,680	63,887	50,076
Other	18,811	18,965	18,538
Secured borrowings	122,952	115,504	118,102
Total other borrowings	253,126	265,785	186,716
Subordinated notes	138,888	138,861	138,782
Total Federal Home Loan Bank advances, other borrowings and subordinated notes	$ 1,191,496	$ 1,258,077	$ 732,337