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Business Acquisition (Narrative) (Details) - USD ($) $ in Thousands		9 Months Ended
	Apr. 02, 2018	Sep. 30, 2018	Sep. 30, 2017
Business Acquisition [Line Items]
Net cash consideration		$ 5,794	$ 80,131
Amortization expense		$ 2,617	$ 857
Huntington Steele, LLC
Business Acquisition [Line Items]
Contingent liability, recognition period	5 years
Total purchase price	$ 17,914
Net cash consideration	5,794
Cash acquired from acquisition	125
Contingent purchase price	12,120
Accrued liabilities | Huntington Steele, LLC
Business Acquisition [Line Items]
Contingent purchase price, current	430
Other long-term liabilities | Huntington Steele, LLC
Business Acquisition [Line Items]
Contingent purchase price, noncurrent	$ 11,690

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Business Acquisition, Recognized Identifiable Assets Acquired and Liabilities Assumed, Contingent Liability, Period

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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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The amount of liability arising from an inherited contingency (as defined) which has been recognized as of the acquisition date.

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The cash inflow associated with the acquisition of business during the period (for example, cash that was held by the acquired business).

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