XML 36 R21.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Retirement Plans | 12 Months Ended
--- | ---
Sep. 30, 2018
Retirement Benefits [Abstract] |
Retirement Plans | Retirement Plans We have established defined contribution plans including 401(k) plans. Generally, employees are eligible to participate in the defined contribution plans upon completion of one year of service and in the 401(k) plans upon commencement of employment. For fiscal 2018, 2017 and 2016, employer contributions to the plans were $22.4 million, $11.4 million and $10.7 million, respectively. We have established a non-qualified deferred compensation plan for certain key employees and non-employee directors. Eligible employees and non-employee directors may elect to defer the receipt of salary, incentive payments, restricted stock, PSU and RSU awards, and non-employee director fees, which are generally invested by us in individual variable life insurance contracts we own that are designed to informally fund savings plans of this nature. At September 30, 2018 and October 1, 2017, the consolidated balance sheets reflect assets of $29.4 million and $25.0 million, respectively, related to the deferred compensation plan in "Other long-term assets," and liabilities of $30.2 million and $25.2 million, respectively, related to the deferred compensation plan in "Other long-term liabilities."

X
- Definition Description about retirement plan including 401(k) plans. Also includes disclosure reflecting postretirement benefit arrangements with individual employees, which are generally based on employment contracts between the entity and one or more selected officers or key employees, and which contain a promise by the employer to pay certain amounts at designated future dates, usually including a period after retirement, upon compliance with stipulated requirements. This type of arrangement is distinguished from broader based employee benefit plans as it is usually tailored to the employee. Disclosure also typically includes the amount of related compensation expense recognized during the reporting period and the carrying amount as of the balance sheet date of the related liability. + References No definition available. + Details
Name: | ttek_RetirementPlansAndDeferredCompensationArrangementWithIndividualDisclosurePostretirementBenefitsTextBlock
Namespace Prefix: | ttek_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_CompensationAndRetirementDisclosureAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration