Minimum Regulatory Capital Requirements (Details) $ in Thousands	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Total regulatory capital (to risk-weighted assets)
Actual, Amount	$ 3,187,130	$ 2,906,742
Actual, Ratio	0.1955	0.1789
For Capital Adequacy, Amount	$ 1,304,508	$ 1,299,657
For Capital Adequacy, Ratio	0.08	0.08
To Be Well-Capitalized Under Prompt Corrective Action Provisions, Amount	$ 1,630,634	$ 1,624,571
To Be Well-Capitalized Under Prompt Corrective Action Provisions, Ratio	0.10	0.10
Common equity Tier 1 capital (to risk-weighted assets)
Actual, Amount	$ 3,024,288	$ 2,751,694
Actual, Ratio	0.1855	0.1694
For Capital Adequacy, Amount	$ 733,785	$ 731,057
For Capital Adequacy, Ratio	0.045	0.045
To Be Well-Capitalized Under Prompt Corrective Action Provisions, Amount	$ 1,059,912	$ 1,055,971
To Be Well-Capitalized Under Prompt Corrective Action Provisions, Ratio	0.065	0.065
Tier 1 capital (to risk-weighted assets)
Actual, Amount	$ 3,024,288	$ 2,751,694
Actual, Ratio	0.1855	0.1694
For Capital Adequacy, Amount	$ 978,381	$ 974,743
For Capital Adequacy, Ratio	0.06	0.06
To Be Well-Capitalized Under Prompt Corrective Action Provisions, Amount	$ 1,304,508	$ 1,299,657
To Be Well-Capitalized Under Prompt Corrective Action Provisions, Ratio	0.08	0.08
Tier 1 capital (to average assets) leverage
Actual, Amount	$ 3,024,288	$ 2,751,694
Actual, Ratio	0.1400	0.1203
For Capital Adequacy, Amount	$ 864,206	$ 915,233
For Capital Adequacy, Ratio	0.04	0.04
To Be Well-Capitalized Under Prompt Corrective Action Provisions, Amount	$ 1,080,258	$ 1,144,041
To Be Well-Capitalized Under Prompt Corrective Action Provisions, Ratio	0.05	0.05