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Regulatory Capital Requirements (Details) - USD ($) $ in Thousands | Dec. 31, 2019 | Dec. 31, 2018
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Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] |  |
Capital Conservation Buffer | 5.60% |
Common Equity Tier One Capital | $ 1,317,202 | $ 1,253,394
Common Equity Tier 1 Capital to Risk Weighted Assets | 12.45% | 12.74%
Common Equity Tier One Capital Required for Capital Adequacy | $ 476,260 | $ 442,717
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 plus capital conservation buffer phase-in |  | $ 627,182
Common Equity Tier 1 Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets plus capital conservation buffer phase-in |  | 6.38%
Common Equity Tier One Capital Required for Capital Adequacy - minimum required plus fully phased in capital conservation buffer | $ 740,849 | $ 688,670
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%
Total Capital, Actual Amount | $ 1,439,877 | $ 1,376,555
Total Capital (to risk-weighted assets), Ratio | 13.60% | 13.99%
Total Capital For Capital Adequacy Purposes, Amount | $ 846,685 | $ 787,052
Total Capital (to risk-weighted assets), For Capital Adequacy Purposes, Ratio | 8.00% | 8.00%
Capital Required for Capital Adequacy plus capital conservation buffer phase-in |  | $ 971,517
Capital Required for Capital Adequacy to Risk Weighted Assets plus capital conservation buffer phase-in |  | 9.88%
Capital Required for Capital Adequacy plus capital conservation buffer fully phased-in | $ 1,111,274 | $ 1,033,006
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 | $ 1,317,202 | $ 1,253,394
Tier 1 Capital (to risk-weighted assets), Ratio | 12.45% | 12.74%
Tier 1 Capital For Capital Adequacy Purposes, Amount | $ 635,014 | $ 590,289
Tier 1 Capital (to risk-weighted assets) For Capital Adequacy Purposes, Ratio | 6.00% | 6.00%
Tier One Risk Based Capital Required for Capital Adequacy plus capital conservation buffer phase-in |  | $ 774,754
Tier One Based Capital Required for Capital Adequacy to Risk Weighted Assets plus capital conservation buffer phase-in |  | 7.88%
Tier One Risk Based Capital Required for Capital Adequacy plus capital conservation buffer fully phased-in | $ 899,603 | $ 836,243
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, Actual Amount | $ 1,317,202 | $ 1,253,394
Tier 1 Capital (to average assets), Ratio | 10.17% | 10.24%
Tier 1 Capital For Capital Adequacy Purposes, Amount | $ 517,938 | $ 489,399
Tier 1 Capital (to average assets) For Capital Adequacy Purposes, Ratio | 4.00% | 4.00%
Banking Subsidiaries [Member] |  |
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] |  |
Capital Conservation Buffer | 5.29% |
Common Equity Tier One Capital | $ 1,318,044 | $ 1,274,317
Common Equity Tier 1 Capital to Risk Weighted Assets | 12.46% | 12.96%
Common Equity Tier One Capital Required for Capital Adequacy | $ 475,913 | $ 442,552
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 plus capital conservation buffer phase-in |  | $ 626,948
Common Equity Tier 1 Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets plus capital conservation buffer phase-in |  | 6.38%
Common Equity Tier One Capital Required for Capital Adequacy - minimum required plus fully phased in capital conservation buffer | $ 740,310 | $ 688,414
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 | $ 687,430 | $ 639,241
Common Equity Tier 1 Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets | 6.50% | 6.50%
Total Capital, Actual Amount | $ 1,405,422 | $ 1,362,016
Total Capital (to risk-weighted assets), Ratio | 13.29% | 13.85%
Total Capital For Capital Adequacy Purposes, Amount | $ 846,068 | $ 786,759
Total Capital (to risk-weighted assets), For Capital Adequacy Purposes, Ratio | 8.00% | 8.00%
Capital Required for Capital Adequacy plus capital conservation buffer phase-in |  | $ 971,155
Capital Required for Capital Adequacy to Risk Weighted Assets plus capital conservation buffer phase-in |  | 9.88%
Capital Required for Capital Adequacy plus capital conservation buffer fully phased-in | $ 1,110,464 | $ 1,032,621
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 | $ 1,057,585 | $ 983,448
Total Capital (to risk-weighted assets) To Be Well Capitalized Under Prompt Corrective Action Provision | 10.00% | 10.00%
Tier 1 Capital, Actual Amount | $ 1,318,044 | $ 1,274,317
Tier 1 Capital (to risk-weighted assets), Ratio | 12.46% | 12.96%
Tier 1 Capital For Capital Adequacy Purposes, Amount | $ 634,551 | $ 590,069
Tier 1 Capital (to risk-weighted assets) For Capital Adequacy Purposes, Ratio | 6.00% | 6.00%
Tier One Risk Based Capital Required for Capital Adequacy plus capital conservation buffer phase-in |  | $ 774,465
Tier One Based Capital Required for Capital Adequacy to Risk Weighted Assets plus capital conservation buffer phase-in |  | 7.88%
Tier One Risk Based Capital Required for Capital Adequacy plus capital conservation buffer fully phased-in | $ 898,947 | $ 835,931
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 | $ 846,068 | $ 786,759
Tier 1 Capital (to risk-weighted assets) To Be Well Capitalized Under Prompt Corrective Action Provision, Ratio | 8.00% | 8.00%
Tier 1 Capital, Actual Amount | $ 1,318,044 | $ 1,274,317
Tier 1 Capital (to average assets), Ratio | 10.22% | 10.42%
Tier 1 Capital For Capital Adequacy Purposes, Amount | $ 515,797 | $ 489,254
Tier 1 Capital (to average assets) For Capital Adequacy Purposes, Ratio | 4.00% | 4.00%
Tier 1 Capital To Be Well Capitalized Under Prompt Corrective Provision, Amount | $ 644,746 | $ 611,567
Tier 1 Capital (to average assets) To Be Well Capitalized Under Prompt Corrective Provision, Ratio | 5.00% | 5.00%

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- Definition The minimum Tier One Capital Ratio (Tier one capital divided by risk-weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958570-112826 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1H -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=117337116&loc=d3e65071-112826 + Details
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- Definition The amount of Tier 1 Risk Based Capital required to be categorized as well capitalized under the regulatory framework for prompt corrective action. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
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- Definition The Tier 1 capital ratio (Tier 1 capital divided by risk weighted assets) required to be categorized as "well capitalized" under the regulatory framework for prompt corrective action. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
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- Definition Tier 1 capital divided by risk weighted assets as defined by regulations. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1H -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=117337116&loc=d3e65071-112826 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
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