Noninterest Income - Gains and Losses on Derivatives (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Other Income and Expenses [Abstract]
Gains on exercises, net	$ 23,940	$ 30,047	$ 59,370	$ 90,357
Terminations	(361)	(481)	(1,332)	(2,931)
Changes in fair value, net	30,187	7,995	35,629	19,787
Gains on equity warrant assets, net	$ 53,766	$ 37,561	$ 93,667	$ 107,213