Other Assets (Schedule of Other Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Accrued interest receivable	$ 56,042	$ 52,835
Derivative assets	47,501	43,549
Low-income housing tax credit investments	23,021	14,782
Prepaid expenses	19,013	15,021
Investment in unconsolidated trust subsidiaries	14,277	14,277
Commercial servicing asset	6,391	7,944
Income taxes receivable	4,841	10,715
Other	56,551	44,228
Total	$ 227,637	$ 203,351