Borrowings, Short-Term Borrowings (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Borrowings [Abstract]
FHLB, unused lines of credit available for short-term financing	$ 3,400,000	$ 3,100,000
Short-term borrowings [Abstract]
Balance at year-end	97,795	168,386
Federal Funds Purchased [Member]
Short-term borrowings [Abstract]
Balance at year-end	0	0	$ 65,000
Average during the year	17	14,727	47,137
Maximum month end balance	$ 0	$ 40,000	$ 80,000
Weighted average rate during the year	0.11%	2.05%	3.90%
Weighted average rate at year-end	0.00%	0.00%	2.84%
Securities Sold Under Repurchase Agreements [Member]
Short-term borrowings [Abstract]
Balance at year-end	$ 97,795	$ 143,386	$ 143,775
Average during the year	100,519	154,383	123,337
Maximum month end balance	$ 135,623	$ 176,840	$ 146,410
Weighted average rate during the year	0.13%	0.17%	0.33%
Weighted average rate at year-end	0.11%	0.20%	0.40%
Other Short-Term Borrowings [Member]
Short-term borrowings [Abstract]
Balance at year-end	$ 0	$ 25,000	$ 446,500
Average during the year	1,302	183,699	403,453
Maximum month end balance	$ 0	$ 366,500	$ 576,000
Weighted average rate during the year	2.02%	1.55%	1.85%
Weighted average rate at year-end	0.00%	1.99%	1.73%