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Loans Receivable and Allowance for Credit Losses (Loans Modified as TDRs that Subsequently Defaulted) (Details) $ in Thousands | 12 Months Ended
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Dec. 31, 2017 USD ($) loan | Dec. 31, 2016 USD ($) loan | Dec. 31, 2015 USD ($) loan
Financing Receivable, Modifications [Line Items] |  |  |
Period beyond which a TDR generally become delinquent | 90 days |  |
Additional funds committed to lend to borrowers whose terms have been modified | $ 5,100 | $ 9,900 |
Non-PCI impaired loans | Commercial Lending | C&I |  |  |
Financing Receivable, Modifications [Line Items] |  |  |
Number of Loans | loan | 3 | 0 | 0
Recorded Investment | $ 8,659 | $ 0 | $ 0
Non-PCI impaired loans | Commercial Lending | CRE |  |  |
Financing Receivable, Modifications [Line Items] |  |  |
Number of Loans | loan | 0 | 2 | 0
Recorded Investment | $ 0 | $ 3,150 | $ 0
Non-PCI impaired loans | Commercial Lending | Construction and land |  |  |
Financing Receivable, Modifications [Line Items] |  |  |
Number of Loans | loan | 0 | 1 | 0
Recorded Investment | $ 0 | $ 4,883 | $ 0
Non-PCI impaired loans | Consumer Lending | Residential loan | Single-family |  |  |
Financing Receivable, Modifications [Line Items] |  |  |
Number of Loans | loan | 0 | 0 | 1
Recorded Investment | $ 0 | $ 0 | $ 279

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- Definition Duration of delinquency related to troubled debt restructuring loans where it becomes a nonaccrual loan and is considered to have defaulted. + References No definition available. + Details
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- Definition Number of financing receivables that have been modified by troubled debt restructurings within the previous 12 months and for which there was a payment default. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 34 -URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953682-111524 + Details
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- Definition Amount of investment related to financing receivables modified by troubled debt restructurings within the previous 12 months, for which there was a payment default. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 34 -URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953682-111524 + Details
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- Definition Reflects the unfunded portion of contractual agreements to lend funds to borrowers for loans whose terms have been modified by troubled debt restructuring. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 40 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=82895541&loc=d3e18794-111554 + Details
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