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Goodwill and Other Intangible Assets - Summary of Goodwill and Intangible Assets (Detail) - USD ($) $ in Thousands | Sep. 30, 2019 | Dec. 31, 2018 | Sep. 30, 2018 | Dec. 31, 2017
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Goodwill and Intangible Assets Disclosure [Abstract] |  |  |  |
Goodwill, gross carrying amount | $ 11,459 | $ 11,459 |  |
Intangible assets, gross carrying amount | 4,240 | 4,240 |  |
Goodwill and intangible assets, gross carrying amount, total | 15,699 | 15,699 |  |
Goodwill, accumulated amortization | 0 | 0 |  |
Intangible assets, accumulated amortization | (1,052) | (314) |  |
Goodwill, net book value | 11,459 | 11,459 | $ 4,186 | $ 0
Intangible assets, net book value | 3,188 | 3,926 |  |
Goodwill and intangible assets, net book value | $ 14,647 | $ 15,385 |  |

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- Definition Gross carrying amount of finite-lived intangible assets and goodwill. Goodwill is an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Intangible assets are assets, not including financial assets, lacking physical substance. + References No definition available. + Details
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- Definition Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275 + Details
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- Definition Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 928 -SubTopic 340 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6473545&loc=d3e61844-108004 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275 + Details
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