Regulatory Capital - U.S. Basel III Regulatory Requirements (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Actual Amount
Common Equity Tier 1 Capital (to Risk-Weighted Assets)	$ 3,236,740	$ 3,314,657
Tier 1 Capital (to Risk-Weighted Assets)	3,236,740	3,314,657
Total Capital (to Risk-Weighted Assets)	3,519,403	3,410,183
Tier 1 Capital (to Average Assets)	$ 3,236,740	$ 3,314,657
Actual Ratio
Common Equity Tier 1 Capital (to Risk-Weighted Assets)	14.30%	14.10%
Tier 1 Capital (to Risk-Weighted Assets)	0.143	0.141
Total Capital (to Risk-Weighted Assets)	0.156	0.145
Tier 1 Capital (to Average Assets)	0.112	0.111
U.S. Basel III Regulatory Requirements, Amount
Common Equity Tier 1 Capital (to Risk-Weighted Assets)	$ 1,579,060	$ 1,643,132
Tier 1 Capital (to Risk-Weighted Assets)	1,917,430	1,995,232
Total Capital (to Risk-Weighted Assets)	2,368,590	2,464,699
Tier 1 Capital (to Average Assets)	$ 1,153,540	$ 1,198,808
U.S. Basel III Regulatory Requirements, Ratio
Common Equity Tier 1 Capital (to Risk-Weighted Assets)	7.00%	7.00%
Tier 1 Capital (to Risk-Weighted Assets)	0.085	0.085
Total Capital (to Risk-Weighted Assets)	0.105	0.105
Tier 1 Capital (to Average Assets)	0.040	0.040