Borrowings (Average balances and rates) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Debt Disclosure [Abstract]
Average balance during period	$ 4,458,463	$ 225,411	$ 194,575
Maximum month end balance during period	$ 6,400,000	$ 905,000	$ 645,000
Weighted average rate during period	5.30%	4.10%	1.60%
Weighted average rate at December 31	5.60%	4.70%	7.10%