Regulatory Capital Requirements (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Capital Conservation Buffer	5.98%
Common Equity Tier One Capital	$ 1,885,860	$ 1,710,981
Common Equity Tier 1 Capital to Risk Weighted Assets	12.87%	13.01%
Common Equity Tier One Capital Required for Capital Adequacy	$ 659,248	$ 591,585
Common Equity Tier 1 Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets	4.50%	4.50%
Common Equity Tier One Capital Required for Capital Adequacy - minimum required plus fully phased in capital conservation buffer	$ 1,025,498	$ 920,244
Common Equity Tier 1 Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets plus capital conservation buffer fully phased-in	7.00%	7.00%
Tier 1 Capital, Actual Amount	$ 1,885,860	$ 1,710,981
Tier 1 Capital (to risk-weighted assets), Ratio	0.1287	0.1301
Tier 1 Capital For Capital Adequacy Purposes, Amount	$ 878,998	$ 788,780
Tier 1 Capital (to risk-weighted assets) For Capital Adequacy Purposes, Ratio	0.0600	0.0600
Tier One Risk Based Capital Required for Capital Adequacy plus capital conservation buffer fully phased-in	$ 1,245,247	$ 1,117,439
Tier One Based Capital Required for Capital Adequacy to Risk Weighted Assets plus capital conservation buffer fully phased-in	8.50%	8.50%
Total Capital, Actual Amount	$ 2,048,700	$ 1,868,192
Total Capital (to risk-weighted assets), Ratio	0.1398	0.1421
Total Capital For Capital Adequacy Purposes, Amount	$ 1,171,997	$ 1,051,707
Total Capital (to risk-weighted assets), For Capital Adequacy Purposes, Ratio	0.0800	0.0800
Capital Required for Capital Adequacy plus capital conservation buffer fully phased-in	$ 1,538,246	$ 1,380,366
Capital Required for Capital Adequacy to Risk Weighted Assets plus capital conservation buffer fully phased-in	10.50%	10.50%
Tier 1 Capital, Actual Amount	$ 1,885,860	$ 1,710,981
Tier 1 Capital (to average assets), Ratio	0.0934	0.0855
Tier 1 Capital For Capital Adequacy Purposes, Amount	$ 807,791	$ 800,615
Tier 1 Capital (to average assets) For Capital Adequacy Purposes, Ratio	0.0400	0.0400
Banking Subsidiaries
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Capital Conservation Buffer	5.97%
Common Equity Tier One Capital	$ 1,892,755	$ 1,716,186
Common Equity Tier 1 Capital to Risk Weighted Assets	12.93%	13.06%
Common Equity Tier One Capital Required for Capital Adequacy	$ 658,773	$ 591,154
Common Equity Tier 1 Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets	4.50%	4.50%
Common Equity Tier One Capital Required for Capital Adequacy - minimum required plus fully phased in capital conservation buffer	$ 1,024,758	$ 919,754
Common Equity Tier 1 Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets plus capital conservation buffer fully phased-in	7.00%	7.00%
Common Equity Tier One Risk Based Capital Required to be Well Capitalized	$ 951,561	$ 853,890
Common Equity Tier 1 Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets	6.50%	6.50%
Tier 1 Capital, Actual Amount	$ 1,892,755	$ 1,716,186
Tier 1 Capital (to risk-weighted assets), Ratio	0.1293	0.1306
Tier 1 Capital For Capital Adequacy Purposes, Amount	$ 878,364	$ 788,206
Tier 1 Capital (to risk-weighted assets) For Capital Adequacy Purposes, Ratio	0.0600	0.0600
Tier One Risk Based Capital Required for Capital Adequacy plus capital conservation buffer fully phased-in	$ 1,244,349	$ 1,116,625
Tier One Based Capital Required for Capital Adequacy to Risk Weighted Assets plus capital conservation buffer fully phased-in	8.50%	8.50%
Tier 1 Capital To Be Well Capitalized Under Prompt Corrective Action Provision, Amount	$ 1,171,152	$ 1,050,941
Tier 1 Capital (to risk-weighted assets) To Be Well Capitalized Under Prompt Corrective Action Provision, Ratio	0.0800	0.0800
Total Capital, Actual Amount	$ 2,045,595	$ 1,863,397
Total Capital (to risk-weighted assets), Ratio	0.1397	0.1418
Total Capital For Capital Adequacy Purposes, Amount	$ 1,171,152	$ 1,050,941
Total Capital (to risk-weighted assets), For Capital Adequacy Purposes, Ratio	0.0800	0.0800
Capital Required for Capital Adequacy plus capital conservation buffer fully phased-in	$ 1,537,137	$ 1,379,360
Capital Required for Capital Adequacy to Risk Weighted Assets plus capital conservation buffer fully phased-in	10.50%	10.50%
Total Capital To Be Well Capitalized Under Prompt Corrective Action Provision, Amount	$ 1,463,940	$ 1,313,677
Total Capital (to risk-weighted assets) To Be Well Capitalized Under Prompt Corrective Action Provision	0.1000	0.1000
Tier 1 Capital, Actual Amount	$ 1,892,755	$ 1,716,186
Tier 1 Capital (to average assets), Ratio	0.0947	0.0860
Tier 1 Capital For Capital Adequacy Purposes, Amount	$ 799,485	$ 798,206
Tier 1 Capital (to average assets) For Capital Adequacy Purposes, Ratio	0.0400	0.0400
Tier 1 Capital To Be Well Capitalized Under Prompt Corrective Provision, Amount	$ 999,356	$ 997,757
Tier 1 Capital (to average assets) To Be Well Capitalized Under Prompt Corrective Provision, Ratio	0.0500	0.0500