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Regulatory Capital Requirements (Details) - USD ($) $ in Thousands | Dec. 31, 2016 | Dec. 31, 2015
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Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] |  |
Capital Conservation Buffer | 4.6347% |
Common Equity Tier 1 Capital | $ 873,217 | $ 852,731
Common Equity Tier 1 Capital to Risk Weighted Assets | 11.645% | 11.94%
Common Equity Tier One Risk Based Capital Required for Capital Adequacy | $ 337,439 | $ 321,370
Common Equity Tier 1 Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets | 4.50% | 4.50%
Total Capital, Actual Amount | $ 947,436 | $ 924,284
Total Capital (to risk-weighted assets), Ratio | 12.6347% | 12.94%
Total Capital For Capital Adequacy Purposes, Amount | $ 599,892 | $ 571,324
Total Capital (to risk-weighted assets), For Capital Adequacy Purposes, Ratio | 8.00% | 8.00%
Tier 1 Capital, Actual Amount | $ 874,688 | $ 853,182
Tier 1 Capital (to risk-weighted assets), Ratio | 11.6646% | 11.95%
Tier 1 Capital For Capital Adequacy Purposes, Amount | $ 449,919 | $ 428,493
Tier 1 Capital (to risk-weighted assets) For Capital Adequacy Purposes, Ratio | 6.00% | 6.00%
Tier 1 Capital, Actual Amount | $ 874,688 | $ 853,182
Tier 1 Capital (to average assets), Ratio | 9.5526% | 10.03%
Tier 1 Capital For Capital Adequacy Purposes, Amount | $ 366,263 | $ 340,420
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 | 4.4756% |
Common Equity Tier 1 Capital | $ 862,381 | $ 839,127
Common Equity Tier 1 Capital to Risk Weighted Assets | 11.5051% | 11.76%
Common Equity Tier One Risk Based Capital Required for Capital Adequacy | $ 337,304 | $ 321,168
Common Equity Tier 1 Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets | 4.50% | 4.50%
Common Equity Tier One Risk Based Capital Required to be Well Capitalized | $ 487,217 | $ 463,909
Common Equity Tier 1 Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets | 6.50% | 6.50%
Total Capital, Actual Amount | $ 935,129 | $ 910,229
Total Capital (to risk-weighted assets), Ratio | 12.4756% | 12.75%
Total Capital For Capital Adequacy Purposes, Amount | $ 599,652 | $ 570,965
Total Capital (to risk-weighted assets), For Capital Adequacy Purposes, Ratio | 8.00% | 8.00%
Total Capital To Be Well Capitalized Under Prompt Corrective Action Provision, Amount | $ 749,565 | $ 713,706
Total Capital (to risk-weighted assets) To Be Well Capitalized Under Prompt Corrective Action Provision | 10.00% | 10.00%
Tier 1 Capital, Actual Amount | $ 862,381 | $ 839,127
Tier 1 Capital (to risk-weighted assets), Ratio | 11.5051% | 11.76%
Tier 1 Capital For Capital Adequacy Purposes, Amount | $ 449,739 | $ 428,223
Tier 1 Capital (to risk-weighted assets) For Capital Adequacy Purposes, Ratio | 6.00% | 6.00%
Tier 1 Capital To Be Well Capitalized Under Prompt Corrective Action Provision, Amount | $ 599,652 | $ 570,965
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 | $ 862,381 | $ 839,127
Tier 1 Capital (to average assets), Ratio | 9.4275% | 9.89%
Tier 1 Capital For Capital Adequacy Purposes, Amount | $ 365,902 | $ 339,405
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 | $ 457,378 | $ 424,256
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 Total risk based capital ratio (total capital divided by risk weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958568-112826 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1H -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=35709795&loc=d3e65071-112826 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958570-112826 + Details
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- Definition The minimum amount of Tier 1 Risk Based Capital required for capital adequacy purposes under the regulatory framework for prompt corrective action. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1H -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=35709795&loc=d3e65071-112826 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958568-112826 + Details
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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://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958568-112826 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958570-112826 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1H -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=35709795&loc=d3e65071-112826 + 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://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958568-112826 + Details
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