Other Assets (Schedule of Other Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Derivative assets	$ 342,510	$ 150,574
Low-income housing tax credit investments	108,549	88,215
Accrued interest receivable	83,804	70,210
Prepaid expenses	30,890	31,456
Income taxes receivable	23,188	16,274
Investment in unconsolidated trust subsidiaries	13,962	13,962
Insurance premium receivable	10,701	10,415
Commercial servicing asset	6,144	5,133
Other real estate owned	1,810	3,295
Other	47,471	44,667
Total other assets	$ 669,029	$ 434,201