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Business Combinations - Acquisition Method for Recording Business Combinations (Detail) - USD ($) shares in Thousands |  | 6 Months Ended
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Jun. 26, 2018 | Jun. 30, 2018
Business Acquisition [Line Items] |  |
Common Shares Issued |  | 273
Common Share Value | $ 24,400,000 | $ 15,900,000
Cash Paid |  | 424,200,000
Accrued Liability |  | 400,000
Escrow Deposited |  | 35,300,000
Recorded Earnout Payable |  | 31,000,000
Total Recorded Purchase Price |  | 506,800,000
Maximum Potential Earnout Payable |  | $ 71,100,000
Market Financial Group, Ltd and Austin Consulting Group Inc. (MFG) [Member] |  |
Business Acquisition [Line Items] |  |
Common Shares Issued |  | 53
Common Share Value |  | $ 3,700,000
Cash Paid |  | 33,900,000
Escrow Deposited |  | 4,200,000
Recorded Earnout Payable |  | 4,000,000
Total Recorded Purchase Price |  | 45,800,000
Maximum Potential Earnout Payable |  | 7,000,000
McGregor & Associates (M&A) [Member] |  |
Business Acquisition [Line Items] |  |
Cash Paid |  | 13,500,000
Escrow Deposited |  | 2,500,000
Recorded Earnout Payable |  | 5,100,000
Total Recorded Purchase Price |  | 21,100,000
Maximum Potential Earnout Payable |  | 12,000,000
Pronto Insurance (PI) [Member] |  |
Business Acquisition [Line Items] |  |
Cash Paid |  | 294,800,000
Escrow Deposited |  | 18,700,000
Total Recorded Purchase Price |  | $ 313,500,000
Sixteen Other Acquisitions [Member] |  |
Business Acquisition [Line Items] |  |
Common Shares Issued |  | 220
Common Share Value |  | $ 12,200,000
Cash Paid |  | 82,000,000
Accrued Liability |  | 400,000
Escrow Deposited |  | 9,900,000
Recorded Earnout Payable |  | 21,900,000
Total Recorded Purchase Price |  | 126,400,000
Maximum Potential Earnout Payable |  | $ 52,100,000

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- Definition Number of shares of equity interests issued or issuable to acquire entity. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (b)(4) -URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479 + Details
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- Definition Amount of equity interests of the acquirer, including instruments or interests issued or issuable in consideration for the business combination. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 30 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=109124213&loc=d3e6613-128477 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 30 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=109124213&loc=d3e6578-128477 + Details
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- Definition The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 13 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3213-108585 + Details
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