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Allowance for Credit Losses - Summary of Allowance for Credit Losses and Recorded Investments (Details) - USD ($) $ in Thousands | Jun. 30, 2020 | Mar. 31, 2020 | Jan. 01, 2020 | Dec. 31, 2019 | Jun. 30, 2019 | Mar. 31, 2019 | Dec. 31, 2018
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Financing Receivable, Allowance for Credit Loss [Line Items] |  |  |  |  |  |  |  |
Allowance for Loan Losses, Individually Evaluated for Impairment |  |  |  |  | $ 2,200 |  |  |
Allowance for Loan Losses, Collectively Evaluated for Impairment |  |  |  |  | 60,024 |  |  |
Total | $ 114,609 |  | $ 96,850 | $ 62,224 | 62,224 | $ 61,479 | $ 61,409 | $ 60,996
Portfolio Loans, Individually Evaluated for Impairment |  |  |  |  | 75,337 |  |  |
Portfolio Loans, Collectively Evaluated for Impairment |  |  |  |  | 7,061,815 |  |  |
Total | $ 7,548,558 | [1] |  |  | 7,137,152 |  |  |
Commercial real estate |  |  |  |  |  |  |  |
Financing Receivable, Allowance for Credit Loss [Line Items] |  |  |  |  |  |  |  |
Allowance for Loan Losses, Individually Evaluated for Impairment |  |  |  |  | 2,023 |  |  |
Allowance for Loan Losses, Collectively Evaluated for Impairment |  |  |  |  | 28,554 |  |  |
Total |  |  |  |  | 30,577 |  |  |
Portfolio Loans, Individually Evaluated for Impairment |  |  |  |  | 47,920 |  |  |
Portfolio Loans, Collectively Evaluated for Impairment |  |  |  |  | 3,368,598 |  |  |
Total |  |  |  |  | 3,416,518 |  |  |
Commercial and industrial |  |  |  |  |  |  |  |
Financing Receivable, Allowance for Credit Loss [Line Items] |  |  |  |  |  |  |  |
Allowance for Loan Losses, Individually Evaluated for Impairment |  |  |  |  | 55 |  |  |
Allowance for Loan Losses, Collectively Evaluated for Impairment |  |  |  |  | 15,626 |  |  |
Total |  |  |  |  | 15,681 |  |  |
Portfolio Loans, Individually Evaluated for Impairment |  |  |  |  | 17,606 |  |  |
Portfolio Loans, Collectively Evaluated for Impairment |  |  |  |  | 1,703,227 |  |  |
Total |  |  |  |  | 1,720,833 |  |  |
Commercial construction |  |  |  |  |  |  |  |
Financing Receivable, Allowance for Credit Loss [Line Items] |  |  |  |  |  |  |  |
Allowance for Loan Losses, Individually Evaluated for Impairment |  |  |  |  | 113 |  |  |
Allowance for Loan Losses, Collectively Evaluated for Impairment |  |  |  |  | 7,787 |  |  |
Total |  |  |  |  | 7,900 |  |  |
Portfolio Loans, Individually Evaluated for Impairment |  |  |  |  | 1,914 |  |  |
Portfolio Loans, Collectively Evaluated for Impairment |  |  |  |  | 373,531 |  |  |
Total |  |  |  |  | 375,445 |  |  |
Consumer real estate |  |  |  |  |  |  |  |
Financing Receivable, Allowance for Credit Loss [Line Items] |  |  |  |  |  |  |  |
Allowance for Loan Losses, Individually Evaluated for Impairment |  |  |  |  | 0 |  |  |
Allowance for Loan Losses, Collectively Evaluated for Impairment |  |  |  |  | 6,337 |  |  |
Total |  |  |  |  | 6,337 |  |  |
Portfolio Loans, Individually Evaluated for Impairment |  |  |  |  | 7,884 |  |  |
Portfolio Loans, Collectively Evaluated for Impairment |  |  |  |  | 1,537,439 |  |  |
Total |  |  |  |  | 1,545,323 |  |  |
Other consumer |  |  |  |  |  |  |  |
Financing Receivable, Allowance for Credit Loss [Line Items] |  |  |  |  |  |  |  |
Allowance for Loan Losses, Individually Evaluated for Impairment |  |  |  |  | 9 |  |  |
Allowance for Loan Losses, Collectively Evaluated for Impairment |  |  |  |  | 1,720 |  |  |
Total |  |  |  |  | 1,729 |  |  |
Portfolio Loans, Individually Evaluated for Impairment |  |  |  |  | 13 |  |  |
Portfolio Loans, Collectively Evaluated for Impairment |  |  |  |  | 79,020 |  |  |
Total |  |  |  |  | $ 79,033 |  |  |
[1] | We had 2,360 loans that were modified totaling $1.4 billion under the CARES Act at June 30, 2020. These customers were not considered past due as a result of their delayed payments. Upon exiting the loan modification deferral program, the measurement of loan delinquency will resume where it left off upon entry into the program. Due to the modification program, this delinquency table may not accurately reflect the credit risk associated with these loans.

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- Definition Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953423-111524 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(7)(2)) -URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=121599878&loc=SL82895884-210446 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 50 -Paragraph 13 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919249-210447 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 50 -Paragraph 13 -Subparagraph (f) -URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919249-210447 + Details
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