Acquisitions - Summary of Amounts Preliminarily Allocated to Acquired Assets and Assumed Liabilities (Detail) - USD ($) $ in Thousands |
9 Months Ended | ||
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Sep. 30, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
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| Business Acquisition [Line Items] | |||
| Goodwill | $ 63,675 | $ 25,168 | $ 25,168 |
| Cortina Asset Management, LLC | |||
| Business Acquisition [Line Items] | |||
| Goodwill | 36,324 | ||
| Customer relationships (15 years) | 21,500 | ||
| Aggregate purchase amount | $ 57,824 |
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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- Definition Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Amount of intangible assets, excluding goodwill, acquired at the acquisition date. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Details
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