FHLB Advances, Other Borrowings and Subordinated Notes (Summary of Debt) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Debt Disclosure [Abstract]
FHLB advances	$ 468,962	$ 153,831	$ 419,632
Other borrowings:
Notes payable	41,216	52,445	56,191
Short-term borrowings	19,959	61,809	33,173
Other	49,502	18,154	18,360
Secured borrowings	141,003	130,078	133,642
Total other borrowings	251,680	262,486	241,366
Subordinated notes	139,052	138,971	138,943
Total FHLB advances, other borrowings and subordinated notes	$ 859,694	$ 555,288	$ 799,941