Securities (Narrative) (Details)	3 Months Ended
	Mar. 31, 2020 USD ($) security	Mar. 31, 2019 USD ($)	Dec. 31, 2019 USD ($) security
Unrealized Loss
Allowance for loan losses	$ 557,003,000	$ 317,894,000	$ 358,287,000
Number of available-for-sale debt securities in an unrealized loss position | security	56		101
Provision for credit losses	$ 73,870,000	22,579,000
Collateralized loan obligations (“CLOs”)
Unrealized Loss
Number of available-for-sale debt securities in an unrealized loss position | security	3		3
U.S. government agency and U.S. government sponsored enterprise mortgage-backed securities
Unrealized Loss
Number of available-for-sale debt securities in an unrealized loss position | security	32		57
Asset-backed securities
Unrealized Loss
Number of available-for-sale debt securities in an unrealized loss position | security	4
U.S. government agency and U.S. government-sponsored enterprise debt securities
Unrealized Loss
Number of available-for-sale debt securities in an unrealized loss position | security			14
AFS debt securities
Unrealized Loss
Allowance for loan losses	$ 0
AFS debt securities, accrued interest	14,400,000
OTTI credit losses		$ 0
Provision for credit losses	$ 0