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Business Combinations - Acquisition Method for Recording Business Combinations (Parenthetical) (Detail) | 9 Months Ended
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Sep. 30, 2018
Market Financial Group, Ltd and Austin Consulting Group Inc. (MFG) [Member] |
Business Acquisition [Line Items] |
Effective Date of Acquisition | Jan. 01, 2018
McGregor & Associates (M&A) [Member] |
Business Acquisition [Line Items] |
Effective Date of Acquisition | Mar. 01, 2018
Pronto Insurance (PI) [Member] |
Business Acquisition [Line Items] |
Effective Date of Acquisition | Jun. 05, 2018
Reassurance Holdings, Inc (RHI) [Member] |
Business Acquisition [Line Items] |
Effective Date of Acquisition | Jul. 01, 2018
25 Other Acquisitions [Member] |
Business Acquisition [Line Items] |
Effective Date of Acquisition | 2018

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