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Basis of Presentation - Schedule of Impact of ASU 2016-13 (Details) - USD ($) $ in Thousands | 6 Months Ended | 12 Months Ended |  |  |  |
--- | --- | --- | --- | --- | --- | ---
Jun. 30, 2020 | Dec. 31, 2019 | Dec. 31, 2018 | Mar. 31, 2020 | Jan. 01, 2020 | Jun. 30, 2019 | Mar. 31, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |  |  |  |  |
Loans held for investment, outstanding balance | $ 7,548,558 | [1] | $ 7,137,152 |  |  |  |  |  |
Allowance for credit losses on loans | (114,609) |  | (62,224) |  | $ (60,996) | $ (96,850) | $ (62,224) | $ (61,479) | $ (61,409)
Total loans |  |  |  |  |  |  | 7,074,928 |  |
Net deferred tax asset |  |  |  |  |  |  | 13,206 |  |
Allowance for credit losses on unfunded loan commitments | 7,004 |  | 3,112 |  |  | 6,077 | 3,113 |  |
Retained earnings | $ 692,240 |  | $ 761,083 |  |  |  | 761,083 |  |
Accounting Standards Update [Extensible List] | us-gaap:AccountingStandardsUpdate201613Member |  | us-gaap:AccountingStandardsUpdate201613Member |  | us-gaap:AccountingStandardsUpdate201602Member |  |  |  |
As Reported Under ASU 2016-13 |  |  |  |  |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |  |  |  |  |
Allowance for credit losses on loans |  |  |  |  |  |  | (89,577) |  |
Total loans |  |  |  |  |  |  | 7,047,575 |  |
Net deferred tax asset |  |  |  |  |  |  | 19,317 |  |
Allowance for credit losses on unfunded loan commitments |  |  | $ 4,461 |  |  |  | 4,462 |  |
Retained earnings |  |  |  |  |  |  | 738,493 |  |
Impact of ASU 2016-13 Adoption |  |  |  |  |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |  |  |  |  |
Allowance for credit losses on loans |  |  | (27,352) |  |  |  | (27,353) |  |
Total loans |  |  |  |  |  |  | (27,353) |  |
Net deferred tax asset |  |  |  |  |  |  | 6,111 |  |
Allowance for credit losses on unfunded loan commitments |  |  | 1,349 |  |  |  | 1,349 |  |
Retained earnings |  |  |  |  |  |  | (22,590) |  |
Commercial real estate |  |  |  |  |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |  |  |  |  |
Allowance for credit losses on loans |  |  |  |  | $ (33,707) |  |  | (32,836) | (34,903)
Commercial and industrial |  |  |  |  |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |  |  |  |  |
Allowance for credit losses on loans |  |  |  |  | (11,596) |  |  | (13,227) | (11,996)
Commercial and industrial | Impact of ASU 2016-13 Adoption |  |  |  |  |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |  |  |  |  |
Allowance for credit losses on loans |  |  |  |  |  |  | (9,900) |  |
Commercial construction |  |  |  |  |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |  |  |  |  |
Allowance for credit losses on loans |  |  |  |  | (7,983) |  |  | (7,254) | (6,757)
Consumer real estate |  |  |  |  |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |  |  |  |  |
Allowance for credit losses on loans |  |  |  |  | (6,187) |  |  | (6,571) | (6,178)
Other consumer |  |  |  |  |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |  |  |  |  |
Allowance for credit losses on loans |  |  |  |  | $ (1,523) |  |  | $ (1,591) | $ (1,575)
Commercial | Commercial real estate |  |  |  |  |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |  |  |  |  |
Loans held for investment, outstanding balance | $ 2,862,103 | [1] | 3,059,592 |  |  |  | 3,416,518 |  |
Allowance for credit losses on loans | (57,730) |  | (30,577) |  |  | (42,611) |  |  |
Commercial | Commercial real estate | As Reported Under ASU 2016-13 |  |  |  |  |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |  |  |  |  |
Loans held for investment, outstanding balance |  |  |  |  |  |  | 2,946,319 |  |
Commercial | Commercial real estate | Impact of ASU 2016-13 Adoption |  |  |  |  |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |  |  |  |  |
Loans held for investment, outstanding balance |  |  |  |  |  |  | (470,199) |  |
Allowance for credit losses on loans |  |  | (4,810) |  |  |  |  |  |
Commercial | Commercial and industrial |  |  |  |  |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |  |  |  |  |
Loans held for investment, outstanding balance | 1,682,676 | [1] | 1,480,529 |  |  |  | 1,720,833 |  |
Allowance for credit losses on loans | (19,164) |  | (15,681) |  |  | (19,870) |  |  |
Commercial | Commercial and industrial | As Reported Under ASU 2016-13 |  |  |  |  |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |  |  |  |  |
Loans held for investment, outstanding balance |  |  |  |  |  |  | 1,458,541 |  |
Commercial | Commercial and industrial | Impact of ASU 2016-13 Adoption |  |  |  |  |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |  |  |  |  |
Loans held for investment, outstanding balance |  |  |  |  |  |  | (262,292) |  |
Allowance for credit losses on loans |  |  | (7,853) |  |  |  |  |  |
Commercial | Commercial construction |  |  |  |  |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |  |  |  |  |
Loans held for investment, outstanding balance | 453,098 | [1] | 370,060 |  |  |  | 375,445 |  |
Allowance for credit losses on loans | (8,874) |  | (7,900) |  |  | (6,606) |  |  |
Commercial | Commercial construction | As Reported Under ASU 2016-13 |  |  |  |  |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |  |  |  |  |
Loans held for investment, outstanding balance |  |  |  |  |  |  | 345,263 |  |
Commercial | Commercial construction | Impact of ASU 2016-13 Adoption |  |  |  |  |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |  |  |  |  |
Loans held for investment, outstanding balance |  |  |  |  |  |  | (30,182) |  |
Allowance for credit losses on loans |  |  | 3,376 |  |  |  |  |  |
Commercial | Business banking |  |  |  |  |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |  |  |  |  |
Loans held for investment, outstanding balance | 1,268,835 | [1] | 846,790 |  |  |  | 0 |  |
Allowance for credit losses on loans | (14,404) | [2] | 0 | [2] |  | (13,706) |  |  |
Commercial | Business banking | As Reported Under ASU 2016-13 |  |  |  |  |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |  |  |  |  |
Loans held for investment, outstanding balance |  |  |  |  |  |  | 1,092,908 |  |
Commercial | Business banking | Impact of ASU 2016-13 Adoption |  |  |  |  |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |  |  |  |  |
Loans held for investment, outstanding balance |  |  |  |  |  |  | 1,092,908 |  |
Allowance for credit losses on loans |  |  | (12,898) |  |  |  |  |  |
Consumer | Consumer real estate |  |  |  |  |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |  |  |  |  |
Loans held for investment, outstanding balance | 1,202,113 | [1] | 1,295,207 |  |  |  | 1,545,323 |  |
Allowance for credit losses on loans | (11,585) |  | (6,337) |  |  | (11,200) |  |  |
Consumer | Consumer real estate | As Reported Under ASU 2016-13 |  |  |  |  |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |  |  |  |  |
Loans held for investment, outstanding balance |  |  |  |  |  |  | 1,235,352 |  |
Consumer | Consumer real estate | Impact of ASU 2016-13 Adoption |  |  |  |  |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |  |  |  |  |
Loans held for investment, outstanding balance |  |  |  |  |  |  | (309,971) |  |
Allowance for credit losses on loans |  |  | (4,525) |  |  |  |  |  |
Consumer | Other consumer |  |  |  |  |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |  |  |  |  |
Loans held for investment, outstanding balance | 79,733 | [1] | 84,974 |  |  |  | 79,033 |  |
Allowance for credit losses on loans | $ (2,852) |  | (1,729) |  |  | $ (2,857) |  |  |
Consumer | Other consumer | As Reported Under ASU 2016-13 |  |  |  |  |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |  |  |  |  |
Loans held for investment, outstanding balance |  |  |  |  |  |  | 58,769 |  |
Consumer | Other consumer | Impact of ASU 2016-13 Adoption |  |  |  |  |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |  |  |  |  |
Loans held for investment, outstanding balance |  |  |  |  |  |  | $ (20,264) |  |
Allowance for credit losses on loans |  |  | $ (642) |  |  |  |  |  |
[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.
[2] | In connection with our adoption of ASU 2016-13, we made changes to our loan portfolio segments to align with the methodology applied in determining the allowance under CECL. Our new segmentation breaks out business banking loans from our other loan segments: CRE, C&I, commercial construction, consumer real estate and other consumer. The business banking allowance balance at the beginning of period is included in the other segments and reclassified to business banking through the impact of CECL adoption line.

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