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Interim Consolidated Financial Statements - Additional Information (Detail) - USD ($) $ in Thousands | 3 Months Ended |  |
--- | --- | --- | ---
Mar. 31, 2019 | Jan. 03, 2019 | Jan. 01, 2019
Summary Of Significant Accounting Policy [Line Items] |  |  |
Operating lease right-of-use assets | $ 71,529 |  |
Operating lease liabilities | $ 80,247 |  |
Lease package practical expedients | true |  |
Option to extend description | Some of the Company’s leases include options to extend or terminate the lease. When determining the lease term, these options are included in the measurement and recognition of the Company’s ROU assets and lease liabilities when it is reasonably certain that the Company will exercise the option. |  |
Topic 842 [Member] |  |  |
Summary Of Significant Accounting Policy [Line Items] |  |  |
Operating lease right-of-use assets |  |  | $ 53,300
Operating lease liabilities |  |  | 60,800
Topic 842 [Member] | Restatement Adjustment |  |  |
Summary Of Significant Accounting Policy [Line Items] |  |  |
Deferred rent |  |  | $ 7,500
Topic 842 [Member] | SiriusDecisions, Inc [Member] |  |  |
Summary Of Significant Accounting Policy [Line Items] |  |  |
Operating lease right-of-use assets |  | $ 10,400 |
Operating lease liabilities |  | $ 10,400 |

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- Definition The cumulative difference between the rental payments required by a lease agreement and the rental income or expense recognized on a straight-line basis, or other systematic and rational basis more representative of the time pattern in which use or benefit is granted or derived from the leased property, expected to be recognized in income or expense over the term of the leased property by the lessor or lessee, respectively. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 20 -Section 25 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=77902458&loc=d3e39896-112707 + Details
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- Definition Indicates (true false) whether practical expedients are elected for not reassessing whether any expired or existing contract is or contains lease, lease classification for expired or existing lease, and initial direct cost for any existing lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 10 -Section 65 -Paragraph 1 -Subparagraph (j) -URI http://asc.fasb.org/extlink&oid=113997351&loc=SL77916155-209984 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 10 -Section 65 -Paragraph 1 -Subparagraph (f) -URI http://asc.fasb.org/extlink&oid=113997351&loc=SL77916155-209984 + Details
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- Definition Description of terms and conditions of option to extend lessee's operating lease. Includes, but is not limited to, information about option recognized as part of right-of-use asset and lease liability. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918673-209980 + Details
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- Definition Present value of lessee's discounted obligation for lease payments from operating lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977 + Details
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- Definition Amount of lessee's right to use underlying asset under operating lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 1 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977 + Details
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