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Represents the earn out period for operating income projection used for fair value measurement.

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Business Combination, Contingent Consideration Arrangements, Period

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Price of a single share of a number of saleable stocks paid or offered to be paid in a business combination.

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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.

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Amount of liabilities incurred by the acquirer as part of consideration transferred in a business combination.

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Amount of increase (decrease) in the value of a contingent consideration liability, including, but not limited to, differences arising upon settlement.

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For contingent consideration arrangements recognized in connection with a business combination, this element represents an estimate of the high-end of the potential range (undiscounted) of the consideration which may be paid.

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Amount of liability recognized arising from contingent consideration in a business combination.

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The amount, measured at acquisition-date fair value, of all liabilities assumed that arise from contingencies and were recognized by the entity.

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Amount of other liabilities due within one year or within the normal operating cycle, if longer, assumed at the acquisition date.

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Amount of revenue attributable to disposal group, including, but not limited to, discontinued operation.

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The designation of funds furnished by a borrower to a lender to assure future payments of the borrower's real estate taxes and insurance obligations with respect to a mortgaged property. Escrow deposits may be made for a variety of other purposes such as earnest money and contingent payments. This element excludes replacement reserves which are an escrow separately provided for within the US GAAP taxonomy.

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Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Amount of gain (loss) from sale and disposal of integrated set of activities and assets capable of being conducted and managed for purpose of providing return in form of dividend, lower cost, or other economic benefit to investor, owner, member and participant.

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The amount of debt that an Entity assumes in acquiring a business or in consideration for an asset received in a noncash (or part noncash) acquisition. Noncash is defined as transactions during a period that affect recognized assets or liabilities but that do not result in cash receipts or cash payments in the period. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.

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The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

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The cash inflow associated with the amount received from the sale of a portion of the company's business, for example a segment, division, branch or other business, during the period.

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Acquisitions and Divestitures - Narrative (Details) $ in Thousands		3 Months Ended				9 Months Ended
	Jul. 09, 2019 USD ($)	Mar. 31, 2019 USD ($)	Jul. 01, 2018 USD ($)	Apr. 01, 2018 USD ($) employee	Dec. 31, 2017 USD ($) employee	Jun. 30, 2019 USD ($)	Jul. 01, 2018 USD ($)	Jul. 09, 2019 £ / shares	Jul. 09, 2019 USD ($) employee
Mergers and Acquisitions
Aggregate maximum of contingent consideration						$ 74,100
Contingent earn-out liability						52,300
Proceeds from sale of divested business						$ 0	$ 36,250
Change in contingent consideration			$ 200				$ 2,100
Minimum
Mergers and Acquisitions
Significant unobservable input, earn-out period						2 years
Minimum \| Existing customer contracts
Mergers and Acquisitions
Useful life of intangible assets						1 year
Minimum \| Trade names
Mergers and Acquisitions
Useful life of intangible assets						3 years
Maximum
Mergers and Acquisitions
Significant unobservable input, earn-out period						3 years
Maximum \| Existing customer contracts
Mergers and Acquisitions
Useful life of intangible assets						10 years
Maximum \| Trade names
Mergers and Acquisitions
Useful life of intangible assets						5 years
eGlobalTech
Mergers and Acquisitions
Fair value of acquisition purchase price		$ 48,400
Issuance of promissory note for business acquisition		24,700
Accruals		2,600
Estimated fair value of contingent earn-out obligation		21,100
Aggregate maximum of contingent consideration		$ 25,000
Contingent consideration achievement period		3 years
Glumac
Mergers and Acquisitions
Staff employed \| employee					300
Cash paid to the former owners					$ 20,000
Fair value of acquisition purchase price					38,400
Aggregate maximum of contingent consideration					$ 20,000
Contingent consideration achievement period					3 years
Contingent earn-out liability					$ 18,400
Norman Disney & Young
Mergers and Acquisitions
Staff employed \| employee				700
Cash paid to the former owners				$ 46,900
Amount held in escrow				1,600
Fair value of acquisition purchase price				56,100
Aggregate maximum of contingent consideration				$ 20,200
Contingent consideration achievement period				3 years
Contingent earn-out liability				$ 7,600
Non-core field services business \| Disposed of by sale
Mergers and Acquisitions
Proceeds from sale of divested business			30,200
Revenue from wired and fiber optic communication and infrastructure projects			70,000
Loss on disposition of business			$ 1,700
Subsequent Event \| WYG
Mergers and Acquisitions
Price per share to acquire WYG \| £ / shares								£ 55
Staff employed \| employee									1,600
Debt assumed	$ 12,000
Amount held in escrow									$ 55,000
Fair value of acquisition purchase price	$ 67,000